feat: LTL operators, sampling, and default generators (#17)

* feat(ltl): add Now/Next/Eventually/Implies/Or/And/Not formulas

Replace the fold-with-latch evaluator with a residual-formula reducer.
Each Observe() instantiates a fresh obligation from the root (stripping
an outer Always), reduces each pending obligation against current state,
latches Violated on first failure, and surfaces Pending verdicts for
deferred obligations. Existing Always/Pure/Thunk tests continue to pass.

* feat(ltl): support relative duration for eventually().within()

* feat(proto): add Swipe, PressKey, RecentLogs RPCs

* feat(verifier,runner): formula handles, new action kinds, rich state

- verifier: add formula-spec registry; bindNow/bindNext/bindEventually with
  chainable .implies/.or/.and/.not and .within(n,unit) on eventually; bindFrom
  for uniform sampling. bindAlways keeps accepting plain predicates.
- verifier: store lastTree, lastAction, step time, logs, exceptions on the
  Verifier; SnapshotInput replaces the (snapshots, tree) pair. stateObject now
  produces state.lastAction/time/logs/exceptions matching the TS State type.
- verifier: make taps/swipes/waitOnce/pressKey built-in generators actually
  fire; taps picks a clickable, enabled element from the last hierarchy.
- agent: add exceptions field to Message wire format.
- driver: add Swipe/PressKey/RecentLogs to Driver interface; wire maestro
  client and mock driver. LogEntry exposed for runner consumption.
- runner: apply Swipe/PressKey/Wait actions; collect logcat and exceptions;
  pass lastAction and step time into PushSnapshot.

* feat(spec-api): LTL operators, new actions, richer State

- ltl.ts exports now/next/eventually; always overload accepts a Formula
- types.ts: Formula gains implies/or/and/not; EventuallyFormula adds .within;
  State gains lastAction/time/logs/exceptions; Swipe/PressKey/Wait action types
- actions.ts: Swipe/PressKey/Wait/from constructors; waitOnce + pressKey
  default generators
- tests exercise the chaining, sampling, and new actions through a recorded
  fake runtime

* feat(sidecar): add swipe, pressKey, recentLogs RPC handlers

* feat(sdk-android): capture uncaught exceptions

Install a default uncaught handler on Uatu.start, chained with any
existing handler so Android's crash reporter still runs. Expose
Uatu.reportError for callers to forward caught throwables. A bounded
circular buffer (default 50) drains into each STATE message's new
exceptions field. Protocol.kt serializes/deserializes the field,
matching the Go wire format added to internal/agent/protocol.go.

* feat(spec-api): add @uatu/spec/defaults/properties bundle

* feat(sample-app): exercise new LTL operators + defaults

spec.ts now imports eventually/next/now/from from @uatu/spec and
noUncaughtExceptions from @uatu/spec/defaults/properties. It declares
three properties that exercise the new surface:

- accountCountNonNegative: plain always() safety
- addAccountAdvances: always(now(x).implies(next(y)))
- eventuallyLoggedIn: eventually(p).within(30, "seconds")
- noUncaughtExceptions: imported default

The weighted actions root uses from() for random phone/name sampling
and entries for taps/swipes/waitOnce/pressKey built-ins.

SampleApplication gains a debug hook gated on the system property
uatu.inject_error so the e2e run can synthesize an Uatu.reportError and
verify noUncaughtExceptions violates.

cmd/uatu/test_run.go adds a subpath alias so specs importing
"@uatu/spec/defaults/properties" resolve against the in-tree source
when running from the uatu checkout. The spec-integration tests swap
the old click-counter fixtures for the new login hierarchy.

* feat(trace): record swipe/key/wait details + exceptions

trace.Step gains an Exceptions array so the trace captures the
class/message/stackTrace for each SDK-reported throwable in a step.
trace.Action gains FromX/FromY/ToX/ToY/Key/DurationMillis so the full
payload of Swipe/PressKey/Wait actions is visible in trace.jsonl.

sample-app's debug error hook now gates on ApplicationInfo.DEBUGGABLE
instead of a system property (adb setprop fails on non-rooted
emulators).

internal/driver/maestro/client.go

@@ -77,6 +77,45 @@ func (c *Client) InputText(ctx context.Context, text string) error {
 	return err
 }
 
+func (c *Client) Swipe(ctx context.Context, fromX, fromY, toX, toY int, duration time.Duration) error {
+	_, err := c.stub.Swipe(ctx, &driverpb.SwipeRequest{
+		From:           &driverpb.Point{X: int32(fromX), Y: int32(fromY)},
+		To:             &driverpb.Point{X: int32(toX), Y: int32(toY)},
+		DurationMillis: duration.Milliseconds(),
+	})
+	return err
+}
+
+func (c *Client) PressKey(ctx context.Context, key string) error {
+	_, err := c.stub.PressKey(ctx, &driverpb.PressKeyRequest{Key: key})
+	return err
+}
+
+func (c *Client) RecentLogs(ctx context.Context, since time.Time, minLevel string) ([]driver.LogEntry, error) {
+	sinceMillis := int64(0)
+	if !since.IsZero() {
+		sinceMillis = since.UnixMilli()
+	}
+	response, err := c.stub.RecentLogs(ctx, &driverpb.RecentLogsRequest{
+		SinceUnixMillis: sinceMillis,
+		LevelAtLeast:    minLevel,
+	})
+	if err != nil {
+		return nil, err
+	}
+	entries := response.GetEntries()
+	result := make([]driver.LogEntry, 0, len(entries))
+	for _, entry := range entries {
+		result = append(result, driver.LogEntry{
+			UnixMillis: entry.GetUnixMillis(),
+			Level:      entry.GetLevel(),
+			Tag:        entry.GetTag(),
+			Message:    entry.GetMessage(),
+		})
+	}
+	return result, nil
+}
+
 func (c *Client) Hierarchy(ctx context.Context) (string, error) {
 	response, err := c.stub.Hierarchy(ctx, &driverpb.Empty{})
 	if err != nil {