Add PF2e spell description popovers in stat blocks

Clicking a spell name in a PF2e creature's stat block now opens a
popover (desktop) or bottom sheet (mobile) showing full spell details:
description, traits, rank, range, target, area, duration, defense,
action cost icons, and heightening rules. All data is sourced from
the embedded Foundry VTT spell items already in the bestiary cache.

- Add SpellReference type replacing bare string spell arrays
- Extract full spell data in pf2e-bestiary-adapter (description,
  traits, traditions, range, target, area, duration, defense,
  action cost, heightening, overlays)
- Strip inline heightening text from descriptions to avoid duplication
- Bold save outcome labels (Critical Success/Failure) in descriptions
- Bump DB_VERSION to 6 for cache invalidation
- Add useSwipeToDismissDown hook for mobile bottom sheet
- Portal popover to document.body to escape transformed ancestors

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

specs/004-bestiary/spec.md

@@ -98,6 +98,11 @@ A view button in the search bar (repurposed from the current search icon) opens
 **US-D3 — Responsive Layout (P4)**
 As a DM using the app on different devices, I want the layout to adapt between side-by-side (desktop) and drawer (mobile) so that the stat block is usable regardless of screen size.
 
+**US-D4 — View Spell Descriptions Inline (P2)**
+As a DM running a PF2e encounter, I want to click a spell name in a creature's stat block to see the spell's full description without leaving the stat block, so I can quickly resolve what a spell does mid-combat without consulting external tools.
+
+A click on any spell name in the spellcasting section opens a popover (desktop) or bottom sheet (mobile) showing the spell's description, level, traits, range, action cost, target/area, duration, defense/save, and heightening rules. The data is read directly from the cached creature data (already embedded in NPC JSON from Foundry VTT) — no additional network fetch is required, and the feature works offline once the source has been loaded. Dismiss with click-outside, Escape, or (on mobile) swipe-down.
+
 ### Requirements
 
 - **FR-016**: The system MUST display a stat block panel with full creature information when a creature is selected.
@@ -116,6 +121,13 @@ As a DM using the app on different devices, I want the layout to adapt between s
 - **FR-067**: PF2e stat blocks MUST organize abilities into three sections: top (above defenses), mid (reactions and auras), and bot (active abilities), matching the Foundry VTT PF2e item categorization.
 - **FR-068**: PF2e stat blocks MUST strip HTML tags from Foundry VTT ability descriptions and render them as plain readable text. The HTML-to-text conversion serves the same role as the D&D tag-stripping approach (FR-019).
 - **FR-062**: Bestiary-linked combatant rows MUST display a small book icon (Lucide `BookOpen`) as the dedicated stat block trigger. The icon MUST have a tooltip ("View stat block") and an `aria-label="View stat block"` for accessibility. The book icon is the only way to manually open a stat block from the tracker — clicking the combatant name always enters inline rename mode. Non-bestiary combatant rows MUST NOT display the book icon.
+- **FR-077**: PF2e stat blocks MUST render each spell name in the spellcasting section as an interactive element (clickable button), not as plain joined text.
+- **FR-078**: Clicking a spell name MUST open a popover (desktop) or bottom sheet (mobile) displaying the spell's description, level, traits, range, time/actions, target/area, duration, defense/save, and heightening rules.
+- **FR-079**: The spell description popover/sheet MUST render content from the spell data already embedded in the cached creature JSON — no additional network fetch is required.
+- **FR-080**: The spell description popover/sheet MUST be dismissible by clicking outside, pressing Escape, or (on mobile) swiping the sheet down.
+- **FR-081**: Spell descriptions MUST be processed through the existing Foundry tag-stripping utility before display (consistent with FR-068).
+- **FR-082**: When a spell name has a parenthetical modifier (e.g., "Heal (×3)", "Unfettered Movement (Constant)"), only the spell name portion MUST be the click target; the modifier MUST remain as adjacent plain text.
+- **FR-083**: The spell description display MUST handle both representations of heightening present in Foundry VTT data: `system.heightening` and `system.overlays`.
 
 ### Acceptance Scenarios
 
@@ -131,12 +143,19 @@ As a DM using the app on different devices, I want the layout to adapt between s
 10. **Given** a bestiary-linked combatant row is visible, **When** the user clicks the combatant's name, **Then** inline rename mode is entered — the stat block does NOT open.
 11. **Given** a PF2e creature is selected, **When** the stat block opens, **Then** it displays: name, level, traits as tags, Perception, senses, languages, skills, ability modifiers, AC, Fort/Ref/Will saves, HP, speed, attacks, abilities (top/mid/bot sections), and spellcasting (if applicable). No CR, no ability scores, no legendary actions.
 12. **Given** a PF2e creature with conditional AC (e.g., "with shield raised"), **When** viewing the stat block, **Then** both the standard AC and conditional AC are shown.
+13. **Given** a PF2e creature with spellcasting is displayed in the stat block panel, **When** the DM clicks a spell name in the spellcasting section, **Then** a popover (desktop) or bottom sheet (mobile) opens showing the spell's description, level, traits, range, action cost, and any heightening rules.
+14. **Given** the spell description popover is open, **When** the DM clicks outside it or presses Escape, **Then** the popover dismisses.
+15. **Given** the spell description bottom sheet is open on mobile, **When** the DM swipes the sheet down, **Then** the sheet dismisses.
+16. **Given** a creature from a legacy (non-remastered) PF2e source has spells with pre-remaster names (e.g., "Magic Missile", "True Strike"), **When** the DM clicks one of those spell names, **Then** the spell description still displays correctly using the embedded data.
+17. **Given** a spell name appears as "Heal (×3)" in the stat block, **When** the DM looks at the rendered output, **Then** "Heal" is the clickable element and "(×3)" appears as plain text next to it.
 
 ### Edge Cases
 
 - Creatures with no traits or legendary actions: those sections are omitted from the stat block display.
 - Very long content (e.g., a Lich with extensive spellcasting): the stat block panel scrolls independently of the encounter tracker.
 - Viewport resized from wide to narrow while stat block is open: the layout transitions from panel to drawer.
+- Embedded spell item missing description text: the popover/sheet shows the available metadata (level, traits, range, etc.) and a placeholder note for the missing description.
+- Cached source data from before the spell description feature was added: existing cached entries lack the new per-spell data fields. The IndexedDB schema version MUST be bumped to invalidate old caches and trigger re-fetch (re-normalization from raw Foundry data is not possible because the original raw JSON is not retained).
 
 ---
 
@@ -197,6 +216,7 @@ A DM wants to see which sources are cached, find a specific source, clear a spec
 - **FR-074**: The PF2e index MUST exclude legacy/pre-remaster creatures based on the `publication.remaster` field — only remaster-era content is included by default.
 - **FR-075**: PF2e creature abilities MUST have complete descriptive text in stat blocks. Stubs, generic feat references, and unresolved copy entries are not acceptable.
 - **FR-076**: The PF2e index SHOULD carry per-creature license tagging (ORC/OGL) derived from the Foundry VTT source data.
+- **FR-084**: The PF2e normalization pipeline MUST preserve per-spell data (slug, level, traits, range, time, target, area, duration, defense, description, heightening/overlays) from embedded `items[type=spell]` entries on NPCs, in addition to the spell name. This data MUST be stored in the cached source data and persisted across browser sessions.
 
 ### Acceptance Scenarios
 
@@ -298,7 +318,7 @@ As a DM with a creature pinned, I want to collapse the right (browse) panel inde
 - **Search Index (D&D)** (`BestiaryIndex`): Pre-shipped lightweight dataset keyed by name + source, containing mechanical facts (name, source code, AC, HP average, DEX score, CR, initiative proficiency multiplier, size, type) for all creatures. Sufficient for adding combatants; insufficient for rendering a full stat block.
 - **Search Index (PF2e)** (`Pf2eBestiaryIndex`): Pre-shipped lightweight dataset for PF2e creatures, containing name, source code, AC, HP, level, Perception modifier, size, and creature type. Parallel to the D&D search index but with PF2e-specific fields (level instead of CR, Perception instead of DEX/proficiency).
 - **Source** (`BestiarySource`): A D&D or PF2e publication identified by a code (e.g., "XMM") with a display name (e.g., "Monster Manual (2025)"). Caching and fetching operate at the source level.
-- **Creature (Full)** (`Creature`): A complete creature record with all stat block data (traits, actions, legendary actions, spellcasting, etc.), available only after source data is fetched/uploaded and cached. Identified by a branded `CreatureId`.
+- **Creature (Full)** (`Creature`): A complete creature record with all stat block data (traits, actions, legendary actions, spellcasting, etc.), available only after source data is fetched/uploaded and cached. Identified by a branded `CreatureId`. For PF2e creatures, each spell entry inside `spellcasting` carries full per-spell data (slug, level, traits, range, action cost, target/area, duration, defense, description, heightening) extracted from the embedded `items[type=spell]` data on the source NPC, enabling inline spell description display without additional fetches.
 - **Cached Source Data**: The full normalized bestiary data for a single source, stored in IndexedDB. Contains complete creature stat blocks.
 - **Combatant** (extended): Gains an optional `creatureId` reference to a `Creature`, enabling stat block lookup and stat pre-fill on creation.
 - **Queued Creature**: Transient UI-only state representing a bestiary creature selected for batch-add, containing the creature reference and a count (1+). Not persisted.
@@ -331,3 +351,5 @@ As a DM with a creature pinned, I want to collapse the right (browse) panel inde
 - **SC-019**: PF2e stat blocks render the correct layout (level, three saves, ability modifiers, ability sections) for all PF2e creatures — no D&D-specific fields (CR, ability scores, legendary actions) are shown.
 - **SC-020**: Switching game system immediately changes which creatures appear in search — no page reload required.
 - **SC-021**: Both D&D and PF2e search indexes ship bundled with the app; no network fetch is required to search creatures in either system.
+- **SC-022**: Clicking any spell in a PF2e creature's stat block opens its description display within 100ms — no network I/O is performed.
+- **SC-023**: PF2e spell descriptions are available offline once the bestiary source containing the creature has been cached.