feat(cli): add --timings flag and enrich error tracking fields

Add -t/--timings flag to the sync subcommand, allowing users to opt
into a per-stage timing breakdown after the sync summary. Wire the flag
through main.rs into print_sync() which passes it to the new
should_print_timings() gate.

Enrich the data structures that flow through the sync pipeline so
downstream renderers have full error visibility:

- ProjectSummary gains status_errors (issue-side status enrichment
  failures per project)
- ProjectStatusEnrichment gains path (project path for sub-row display)
- SyncResult gains documents_errored and embedding_failed so the
  summary can surface doc-gen and embed failures separately
- Autocorrect table updated with --timings for fuzzy flag matching

src/cli/mod.rs

@@ -789,6 +789,10 @@ pub struct SyncArgs {
 
     #[arg(long = "no-dry-run", hide = true, overrides_with = "dry_run")]
     pub no_dry_run: bool,
+
+    /// Show detailed timing breakdown for sync stages
+    #[arg(short = 't', long = "timings")]
+    pub timings: bool,
 }
 
 #[derive(Parser)]