fix(topdata): let pinned TLK ids evict stale state owners

The custom palette taxonomy (#46) pins display strings to fixed TLK
ids in tlk/custom.tlk.yml. registerInlineAtID demanded those ids be
free, but .tlk_state.json is a gitignored, per-machine cache: on any
machine built before #46, a ref could have dynamically grabbed a
now-pinned id (e.g. feat:yuanti/alternate_form.feat holding 2689),
failing the build with "TLK id N is already reserved by ...".

Make the pin authoritative over the cache: a stale cached owner on a
pinned id is evicted and reallocated a fresh id when next made active.
Only two pins fighting over one id in custom.tlk.yml is now an error.
This self-heals on the next build without deleting the state file.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

internal/topdata/tlk_native.go

@@ -109,6 +109,7 @@ type tlkCompiler struct {
 	active       map[string]tlkEntryData
 	activeKeys   map[string]struct{}
 	reservedByID map[int]string
+	pinnedByID   map[int]string
 	nextID       int
 }
 
@@ -158,6 +159,7 @@ func newTLKCompiler(sourceDir string, legacy *legacyTLKData) (*tlkCompiler, erro
 		active:       map[string]tlkEntryData{},
 		activeKeys:   map[string]struct{}{},
 		reservedByID: reserved,
+		pinnedByID:   map[int]string{},
 		nextID:       nextID,
 	}
 	if legacy != nil {
@@ -380,12 +382,24 @@ func (c *tlkCompiler) registerInlineAtID(key string, id int, entry tlkEntryData)
 	if id < 0 {
 		return fmt.Errorf("TLK key %q has negative id %d", key, id)
 	}
+	// The pin is authoritative over the per-machine .tlk_state.json cache: a
+	// stale mapping that dynamically grabbed this id on an older build must
+	// yield so the pinned key can take it. Only a genuine clash between two
+	// pins in custom.tlk.yml is an author error.
+	if owner, ok := c.pinnedByID[id]; ok && owner != key {
+		return fmt.Errorf("TLK id %d is pinned by both %q and %q", id, owner, key)
+	}
 	if mapping, ok := c.state.Entries[key]; ok && mapping.ID != id {
-		return fmt.Errorf("TLK key %q changed id from %d to %d", key, mapping.ID, id)
+		// This key held a different cached id; release it so the pin wins.
+		if c.reservedByID[mapping.ID] == key {
+			delete(c.reservedByID, mapping.ID)
+		}
 	}
 	if owner, ok := c.reservedByID[id]; ok && owner != key {
-		return fmt.Errorf("TLK id %d is already reserved by %q", id, owner)
+		// Evict the stale owner; it gets a fresh id when next made active.
+		delete(c.state.Entries, owner)
 	}
+	c.pinnedByID[id] = key
 	c.state.Entries[key] = tlkStateMapping{ID: id}
 	c.reservedByID[id] = key
 	return c.markActive(key, entry)

internal/topdata/topdata_test.go

@@ -2449,6 +2449,55 @@ strings:
 	}
 }
 
+func TestBuildStandaloneTLKPinEvictsStaleStateOwner(t *testing.T) {
+	root := testProjectRoot(t)
+	mkdirAll(t, filepath.Join(root, "topdata", "data", "feat"))
+	mkdirAll(t, filepath.Join(root, "topdata", "tlk"))
+	writeFile(t, filepath.Join(root, "topdata", "base_dialog.json"), "{}\n")
+	writeFile(t, filepath.Join(root, "topdata", "data", "feat", "base.json"), `{
+	  "output": "feat.2da",
+	  "columns": ["LABEL", "FEAT", "DESCRIPTION"],
+	  "rows": [{
+	    "id": 0,
+	    "key": "feat:test",
+	    "LABEL": "TEST_LABEL",
+	    "FEAT": {"tlk": {"key": "feat:test.name", "text": "Test Feat"}},
+	    "DESCRIPTION": "****"
+	  }]
+	}`+"\n")
+	writeFile(t, filepath.Join(root, "topdata", "tlk", "custom.tlk.yml"), `schema: sow-topdata/tlk/v1
+base_strref: 16777216
+strings:
+  - key: sow.module.name
+    text: Shadows Over Westgate
+    id: 50
+`)
+	// Simulate a per-machine state that predates the pinned taxonomy: the feat
+	// ref dynamically grabbed id 50 on an older build, exactly where the pin
+	// now lives. The build must self-heal instead of failing.
+	writeFile(t, filepath.Join(root, "topdata", tlkStateFile),
+		`{"version":1,"language":"en","entries":{"feat:test.name":{"id":50}}}`+"\n")
+
+	if _, err := BuildNative(testProject(root), nil); err != nil {
+		t.Fatalf("BuildNative failed on stale pin collision: %v", err)
+	}
+
+	stateRaw, err := os.ReadFile(filepath.Join(root, "topdata", tlkStateFile))
+	if err != nil {
+		t.Fatalf("read tlk state: %v", err)
+	}
+	var state tlkStateDocument
+	if err := json.Unmarshal(stateRaw, &state); err != nil {
+		t.Fatalf("parse tlk state: %v", err)
+	}
+	if state.Entries["sow.module.name"].ID != 50 {
+		t.Fatalf("pin must own id 50, got %#v", state.Entries["sow.module.name"])
+	}
+	if got := state.Entries["feat:test.name"].ID; got == 50 {
+		t.Fatalf("stale feat ref should have been reallocated off id 50, got %d", got)
+	}
+}
+
 func TestBuildPreservesTLKStateAcrossTextChanges(t *testing.T) {
 	root := testProjectRoot(t)
 	mkdirAll(t, filepath.Join(root, "topdata", "data", "skills"))