refactor(models): preserve legacy claude-opus-4-6 aliases and category mapping

Addresses review feedback on #3486:

1. claude-thinking-legacy-alias now matches both claude-opus-4-6-thinking
   and claude-opus-4-7-thinking, canonicalizing both to claude-opus-4-7.
   The previous diff retargeted the regex to 4-7 only, which dropped
   backward compatibility for users still pinned to the 4-6 thinking
   suffix.

2. MODEL_TO_CATEGORY_MAP keeps the claude-opus-4-6 to unspecified-high
   entry alongside the new 4-7 entry. The map is order-independent from
   MODEL_VERSION_MAP, so preserving the 4-6 key avoids relying on a
   specific migration ordering for legacy agent configs.

3. Fix stale 'Claude Opus 4.6' labels and BDD test comments that the
   sed-based bump missed.

src/hooks/think-mode/switcher.test.ts

@@ -38,7 +38,7 @@ describe("think-mode switcher", () => {
       })
 
       it("should handle claude-opus-4-7 high variant", () => {
-        // given a Claude Opus 4.6 model ID
+        // given a Claude Opus 4.7 model ID
         const variant = getHighVariant("claude-opus-4-7")
 
         // then should return high variant

src/shared/connected-providers-cache.test.ts

@@ -61,7 +61,7 @@ describe("updateConnectedProvidersCache", () => {
 									name: "Anthropic",
 									env: [],
 									models: {
-										"claude-opus-4-7": { id: "claude-opus-4-7", name: "Claude Opus 4.6" },
+										"claude-opus-4-7": { id: "claude-opus-4-7", name: "Claude Opus 4.7" },
 										"claude-sonnet-4-6": { id: "claude-sonnet-4-6", name: "Claude Sonnet 4.6" },
 									},
 								},
@@ -84,7 +84,7 @@ describe("updateConnectedProvidersCache", () => {
 					{ id: "gpt-5.4", name: "GPT-5.4" },
 				],
 				anthropic: [
-					{ id: "claude-opus-4-7", name: "Claude Opus 4.6" },
+					{ id: "claude-opus-4-7", name: "Claude Opus 4.7" },
 					{ id: "claude-sonnet-4-6", name: "Claude Sonnet 4.6" },
 				],
 			})

src/shared/migration/agent-category.ts

@@ -16,6 +16,7 @@ export const MODEL_TO_CATEGORY_MAP: Record<string, string> = {
   "google/gemini-3-flash": "writing",
   "openai/gpt-5.4": "ultrabrain",
   "anthropic/claude-haiku-4-5": "quick",
+  "anthropic/claude-opus-4-6": "unspecified-high",
   "anthropic/claude-opus-4-7": "unspecified-high",
   "anthropic/claude-sonnet-4-6": "unspecified-low",
 }

src/shared/model-capability-aliases.ts

@@ -41,8 +41,8 @@ const EXACT_ALIAS_RULES_BY_MODEL: ReadonlyMap<string, ExactAliasRule> = new Map(
 const PATTERN_ALIAS_RULES: ReadonlyArray<PatternAliasRule> = [
   {
     ruleID: "claude-thinking-legacy-alias",
-    description: "Normalizes the legacy Claude Opus 4.6 thinking suffix to the canonical snapshot ID.",
-    match: (normalizedModelID) => /^claude-opus-4-7-thinking$/.test(normalizedModelID),
+    description: "Normalizes legacy Claude Opus thinking suffixes (4-6, 4-7) to the canonical snapshot ID.",
+    match: (normalizedModelID) => /^claude-opus-4-(?:6|7)-thinking$/.test(normalizedModelID),
     canonicalize: () => "claude-opus-4-7",
   },
   {