Add idle-state classifier and Solo-parity timer tools

Classifies every running child as idle/working/thinking/permission/error
using one of three pluggable strategies (output_activity,
osc_title_stability, osc_title_status) plus optional regex promoters
applied to the tail of recent output. State and last-match reason are
exposed via MCP on ProcessInfo and get_process_status. Per-preset
configuration lives on a new preset.IdleDetection block with bundled
defaults for the first-party claude/codex/opencode presets.

OSC title plumbing is exposed as Emulator.Title(), polled from the
session pump after each emulator write so title-change activity feeds
into the classifier without an extra cgo callback.

The MCP timer surface expands to match Solo: timer_set,
timer_fire_when_idle_any/all, timer_cancel, timer_pause, timer_resume,
timer_list. timer_wait is now a thin wrapper that shares the same
manager so it shows up in timer_list while pending. Timer bodies are
delivered to the owner process through the existing
InjectAsOrchestrator path. Top-level (non-agent) callers can attach
timers to a specific process via owner_process_id; omitting it grants
universal cancel/pause/resume/list privileges.

The sidebar gains a state glyph per process row and appends a
nearest-timer indicator when one is pending or paused.

Tests: idle_test.go covers the classify() pure function across the
three strategies and regex promotion; timers_test.go covers the
manager. Harness scenarios cover output_activity, osc_title_stability,
osc_title_status, and regex promotion, plus timer_set delivery,
cancel, pause/resume, idle_any-on-transition, idle_all-pending, and
idle_all-already-satisfied. A new wait_until_mcp harness step type
polls an MCP method until an assertion holds.

internal/mcp/protocol.go

@@ -73,6 +73,14 @@ func booleanProp(desc string) map[string]any {
 	return map[string]any{"type": "boolean", "description": desc}
 }
 
+func arrayOfStringsProp(desc string) map[string]any {
+	return map[string]any{
+		"type":        "array",
+		"description": desc,
+		"items":       map[string]any{"type": "string"},
+	}
+}
+
 // toolCatalog is the full list advertised via tools/list. Descriptions
 // are intentionally short — clients are expected to fetch help() for
 // detail. Schemas mirror the param structs in tools.go.
@@ -239,12 +247,70 @@ func toolCatalog() []toolDescriptor {
 		},
 		{
 			Name:        "timer_wait",
-			Description: "Sleep server-side for `seconds` and return a timer id (use to pace polling).",
+			Description: "Schedule a delay timer that injects a fixed `[system]` line into your pane when it fires (legacy; prefer timer_set).",
 			InputSchema: objectSchema(map[string]any{
-				"seconds": numberProp("Sleep duration."),
+				"seconds": numberProp("Delay duration."),
 				"label":   stringProp("Optional label for diagnostics."),
 			}, []string{"seconds"}),
 		},
+		{
+			Name:        "timer_set",
+			Description: "Schedule a one-shot delay timer that delivers `body` to the owning agent as a fresh user turn when it fires.",
+			InputSchema: objectSchema(map[string]any{
+				"seconds":          numberProp("Delay duration."),
+				"body":             stringProp("Message delivered verbatim to the owning agent as a user turn when the timer fires."),
+				"label":            stringProp("Optional label for diagnostics."),
+				"owner_process_id": stringProp("Owner process id; defaults to the caller. Top-level callers must supply this explicitly."),
+			}, []string{"seconds", "body"}),
+		},
+		{
+			Name:        "timer_fire_when_idle_any",
+			Description: "Schedule a timer that fires when any watched process enters idle (already-idle entries excluded), or when max_wait_seconds elapses.",
+			InputSchema: objectSchema(map[string]any{
+				"watched":          arrayOfStringsProp("Process ids to watch."),
+				"body":             stringProp("Message delivered verbatim to the owning agent when the timer fires."),
+				"label":            stringProp("Optional label for diagnostics."),
+				"max_wait_seconds": numberProp("Optional cap; 0 means no fallback fire."),
+				"owner_process_id": stringProp("Owner process id; defaults to the caller."),
+			}, []string{"watched", "body"}),
+		},
+		{
+			Name:        "timer_fire_when_idle_all",
+			Description: "Schedule a timer that fires when all watched processes are idle (already-idle entries count as satisfied), or when max_wait_seconds elapses.",
+			InputSchema: objectSchema(map[string]any{
+				"watched":          arrayOfStringsProp("Process ids to watch."),
+				"body":             stringProp("Message delivered verbatim to the owning agent when the timer fires."),
+				"label":            stringProp("Optional label for diagnostics."),
+				"max_wait_seconds": numberProp("Optional cap; 0 means no fallback fire."),
+				"owner_process_id": stringProp("Owner process id; defaults to the caller."),
+			}, []string{"watched", "body"}),
+		},
+		{
+			Name:        "timer_cancel",
+			Description: "Cancel one pending timer owned by the caller.",
+			InputSchema: objectSchema(map[string]any{
+				"timer_id": stringProp("Timer id returned by a previous timer_* call."),
+			}, []string{"timer_id"}),
+		},
+		{
+			Name:        "timer_pause",
+			Description: "Pause one pending timer owned by the caller. Idle-aware timers stop listening to state changes; delay timers preserve their remaining wait.",
+			InputSchema: objectSchema(map[string]any{
+				"timer_id": stringProp("Timer id."),
+			}, []string{"timer_id"}),
+		},
+		{
+			Name:        "timer_resume",
+			Description: "Resume one paused timer owned by the caller.",
+			InputSchema: objectSchema(map[string]any{
+				"timer_id": stringProp("Timer id."),
+			}, []string{"timer_id"}),
+		},
+		{
+			Name:        "timer_list",
+			Description: "List pending and paused timers owned by the caller.",
+			InputSchema: objectSchema(nil, nil),
+		},
 		{
 			Name:        "scratchpad_list",
 			Description: "List shared per-project scratchpad entries.",