feat(dashboard): add Debug Share to the System page (#38600)

* Port from google-gemini/gemini-cli#21541: back up corrupted config.yaml

When config.yaml fails to parse, load_config() silently falls back to
DEFAULT_CONFIG and leaves the broken file on disk. If the user then re-runs
the setup wizard or hermes config set (both rewrite config.yaml), their
broken-but-recoverable overrides are lost for good.

Adapts the policy-file recovery from gemini-cli#21541: on the first parse
warning for a given broken file, snapshot it to config.yaml.corrupt.<ts>.bak
(best-effort, symlink-guarded, size-deduped) and tell the user where it
landed. Unlike Gemini's version we deliberately do NOT reset config.yaml to a
clean state — hermes never silently mutates user config, and leaving it means
a hand-fixed file is re-read on the next load.

Tests: 3 new cases (backup created + content preserved + original untouched;
same-size backup dedup; symlink not copied). E2E verified with isolated
HERMES_HOME and a real tab-indented broken config.

* feat(dashboard): add Debug Share to the System page

Surface `hermes debug share` in the dashboard. The System > Operations
section gets a dedicated card that uploads a redacted report + full logs
and returns the paste URLs as real, copyable links instead of a log tail.

- debug.py: factor a pure build_debug_share() returning structured
  {urls, failures, redacted, auto_delete_seconds}; run_debug_share now
  calls it (CLI output unchanged).
- web_server.py: POST /api/ops/debug-share runs the share core in a
  worker thread and returns the structured payload synchronously (the
  URLs are the whole point — not a backgrounded action).
- api.ts: runDebugShare() + DebugShareResponse.
- SystemPage.tsx: share card with a redaction toggle (on by default),
  per-link + copy-all buttons, and the 6h auto-delete countdown.
- tests: build_debug_share core + endpoint (redact toggle, failure 502,
  token gate).

web/src/lib/api.ts

@@ -853,6 +853,15 @@ export const api = {
   runDump: () => fetchJSON<ActionResponse>("/api/ops/dump", { method: "POST" }),
   runConfigMigrate: () =>
     fetchJSON<ActionResponse>("/api/ops/config-migrate", { method: "POST" }),
+  runDebugShare: (opts?: { redact?: boolean; lines?: number }) =>
+    fetchJSON<DebugShareResponse>("/api/ops/debug-share", {
+      method: "POST",
+      headers: { "Content-Type": "application/json" },
+      body: JSON.stringify({
+        redact: opts?.redact ?? true,
+        lines: opts?.lines ?? 200,
+      }),
+    }),
 
 
   getCheckpoints: () => fetchJSON<CheckpointsResponse>("/api/ops/checkpoints"),
@@ -906,6 +915,16 @@ export interface ActionResponse {
   update_command?: string;
 }
 
+export interface DebugShareResponse {
+  ok: boolean;
+  // label -> paste URL, e.g. { Report: "https://paste.rs/abc", "agent.log": "..." }
+  urls: Record<string, string>;
+  // "label: error" strings for optional full-log uploads that failed.
+  failures: string[];
+  redacted: boolean;
+  auto_delete_seconds: number;
+}
+
 export interface SessionStoreStats {
   total: number;
   active_store: number;