feat(ingest): drive watch loop from notify FS events

CHANGELOG.md

@@ -9,6 +9,9 @@ Cross-package release notes for relayburn. Package changelogs contain package-le
 - `relayburn-cli`: `burn sessions list` human output now keeps full session ids,
   shows a single human-readable last-seen date column, and truncates long
   project paths from the beginning.
+- `relayburn-sdk` / `relayburn-cli`: `burn ingest --watch` now wakes on
+  filesystem events (with burst coalescing and a 30s polling backstop),
+  reducing steady-state polling; pass `--no-fsevents` to force polling.
 
 ## [2.7.0] - 2026-05-09
 

crates/relayburn-cli/src/cli.rs

@@ -156,6 +156,13 @@ pub struct IngestArgs {
     /// on its own (or with `--watch`) so a typo can't silently no-op.
     #[arg(long, requires = "hook")]
     pub quiet: bool,
+
+    /// Force the polling driver in `--watch` mode instead of the
+    /// default `notify`-backed FS-event driver. Use this on
+    /// filesystems where FS events are unreliable (network mounts,
+    /// some Docker setups). Ignored without `--watch`.
+    #[arg(long, requires = "watch")]
+    pub no_fsevents: bool,
 }
 
 /// Per-command flags for `burn mcp-server`. The stdio MCP server speaks