feat(cache-warming,surfaces,metrics,markdown): conversation-scoped surfaces, cache warming + retention, markdown

Consumes the backend cache-warming + cache-rate handoffs end-to-end and adds supporting infra:

- protocol/transport: conversation-scoped surfaces (conversationId on subscribe/invoke/surface + staleness routing); store auto-subscribes the catalog with the focused conversation and re-scopes on switch.
- surface-host: generic Number field renderer + custom rendererId dispatch (graceful skip on unknown).
- cache-warming feature: enabled toggle, min+sec interval, AUTHORITATIVE countdown from the surface's cache-warming-timer nextWarmAt, manual Warm now (POST /chat/warm), lastWarmAt-keyed history, cache-retention stat, expectedCacheRate headline.
- metrics: cross-turn expected-cache (retention) derivation + bubble badge; cache-rate fix needs no code change (inputTokens now total).
- markdown feature: marked + marked-highlight + highlight.js + dompurify, rendered in ChatView.
- fixes (gemini review): {#key activeConversationId} remount of CacheWarmingView to stop history/feedback leaking across tabs; guard NaN interval inputs from committing 0.
- docs/contracts: regenerated transport/ui-contract mirrors; backend-handoff updated (CR-3 resolved).

Verified: svelte-check 0 errors, biome clean, 494 tests pass, vite build OK.

1 files changed, 12 insertions, 0 deletions

diff --git a/bun.lock b/bun.lock
index a231a98..8983dd1 100644
--- a/bun.lock
+++ b/bun.lock
@@ -8,6 +8,10 @@
         "@dispatch/transport-contract": "file:../arch-rewrite/packages/transport-contract",
         "@dispatch/ui-contract": "file:../arch-rewrite/packages/ui-contract",
         "@dispatch/wire": "file:../arch-rewrite/packages/wire",
+        "dompurify": "^3.4.5",
+        "highlight.js": "^11.11.1",
+        "marked": "^18.0.4",
+        "marked-highlight": "^2.2.4",
       },
       "devDependencies": {
         "@biomejs/biome": "^2.4.16",
@@ -320,6 +324,8 @@
 
     "dom-accessibility-api": ["[email protected]", "", {}, "sha512-7ZgogeTnjuHbo+ct10G9Ffp0mif17idi0IyWNVA/wcwcm7NPOD/WEHVP3n7n3MhXqxoIYm8d6MuZohYWIZ4T3w=="],
 
+    "dompurify": ["[email protected]", "", { "optionalDependencies": { "@types/trusted-types": "^2.0.7" } }, "sha512-yb1cEmaOum7wFvOCSQxyfgVlv5D47Rc30iZWoMpbDIWTnJ6grDDQyu2KFJzB2k7u0pMuJcQ1zphH//fFnw2tjQ=="],
+
     "dunder-proto": ["[email protected]", "", { "dependencies": { "call-bind-apply-helpers": "^1.0.1", "es-errors": "^1.3.0", "gopd": "^1.2.0" } }, "sha512-KIN/nDJBQRcXw0MLVhZE9iQHmG68qAVIBg9CqmUYjmQIhgij9U5MFvrqkUL5FbtyyzZuOeOt0zdeRe4UY7ct+A=="],
 
     "enhanced-resolve": ["[email protected]", "", { "dependencies": { "graceful-fs": "^4.2.4", "tapable": "^2.3.3" } }, "sha512-yJN/BOOLxcOW2aQgeif9mSnaUB8KtvmMMp56oA1kx1CRfBKbhZm2pJ+NBY+3eOboHxix8lfjWpHE0Ei5U8RbSA=="],
@@ -370,6 +376,8 @@
 
     "hasown": ["[email protected]", "", { "dependencies": { "function-bind": "^1.1.2" } }, "sha512-T2UbfbBEF32wiepXIsMlTW9+dDYC6wMh/t/vYA4tuOMKqWz/n3vr1NFSxQiyP+zk2mXsoMA/i/7qV6LKut1t1A=="],
 
+    "highlight.js": ["[email protected]", "", {}, "sha512-Xwwo44whKBVCYoliBQwaPvtd/2tYFkRQtXDWj1nackaV2JPXx3L0+Jvd8/qCJ2p+ML0/XVkJ2q+Mr+UVdpJK5w=="],
+
     "html-encoding-sniffer": ["[email protected]", "", { "dependencies": { "whatwg-encoding": "^3.1.1" } }, "sha512-Y22oTqIU4uuPgEemfz7NDJz6OeKf12Lsu+QC+s3BVpda64lTiMYCyGwg5ki4vFxkMwQdeZDl2adZoqUgdFuTgQ=="],
 
     "http-proxy-agent": ["[email protected]", "", { "dependencies": { "agent-base": "^7.1.0", "debug": "^4.3.4" } }, "sha512-T1gkAiYYDWYx3V5Bmyu7HcfcvL7mUrTWiM6yOfa3PIphViJ/gFPbvidQ+veqSOHci/PxBcDabeUNCzpOODJZig=="],
@@ -426,6 +434,10 @@
 
     "magic-string": ["[email protected]", "", { "dependencies": { "@jridgewell/sourcemap-codec": "^1.5.5" } }, "sha512-vd2F4YUyEXKGcLHoq+TEyCjxueSeHnFxyyjNp80yg0XV4vUhnDer/lvvlqM/arB5bXQN5K2/3oinyCRyx8T2CQ=="],
 
+    "marked": ["[email protected]", "", { "bin": { "marked": "bin/marked.js" } }, "sha512-S6GcvALHg6K4ohtu4E7x0a1AqhAjp6cV8KhLSyN9qVapnzJkusVBxZRcIU9AeYsbe6P1hKDusSbEOzGyyuce6w=="],
+
+    "marked-highlight": ["[email protected]", "", { "peerDependencies": { "marked": ">=4 <19" } }, "sha512-PZxisNMJDduSjc0q6uvjsnqqHCXc9s0eyzxDO9sB1eNGJnd/H1/Fu+z6g/liC1dfJdFW4SftMwMlLvsBhUPrqQ=="],
+
     "math-intrinsics": ["[email protected]", "", {}, "sha512-/IXtbwEk5HTPyEwyKX6hGkYXxM9nbj64B+ilVJnC/R6B0pH5G4V3b0pVbL7DBj4tkhBAppbQUlf6F6Xl9LHu1g=="],
 
     "mime-db": ["[email protected]", "", {}, "sha512-sPU4uV7dYlvtWJxwwxHD0PuihVNiE7TyAbQ5SWxDCB9mUYvOgroQOwYQQOKPJ8CIbE+1ETVlOoK1UC2nU3gYvg=="],