Implement linear task chains and recurring maintenance buckets

Backend, web timeline, and Android widget wiring for the last two
unimplemented items from doot-future-task-scheduling-ideas.

Chains: task_chains table + chain_id/chain_position/chain_unlocked on
native_tasks (migration 026), WIP-limit-1 advancement hooked into
CompleteNativeTask, locked tasks excluded from all date-based queries,
5 new /api/widget/chains* endpoints, an N/M position badge on web and
Android widget rows.

Buckets: maintenance_buckets table + bucket_id/bucket_state/
bucket_last_active_at on native_tasks (migration 027),
staleness-then-priority selection scoring, a new RunBucketCycleCheck
scheduler loop, 5 new endpoints including the distinct Defer action, a
Defer button on web and Android widget rows.

Also corrected stale "not yet approved" status headers on the two
already-shipped specs this work depended on (labels/projects, budgets/
availability) -- their headers were never updated after implementation.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EZ7ikw2ukGJFTHE3bJS7zL

1 files changed, 33 insertions, 0 deletions

diff --git a/internal/scheduler/buckets.go b/internal/scheduler/buckets.go
new file mode 100644
index 0000000..5fa242d
--- /dev/null
+++ b/internal/scheduler/buckets.go
@@ -0,0 +1,33 @@
+package scheduler
+
+import (
+	"context"
+	"log"
+	"time"
+
+	"task-dashboard/internal/config"
+	"task-dashboard/internal/store"
+)
+
+// RunBucketCycleCheck ticks every interval, calling RunBucketCycles until
+// ctx is cancelled. Mirrors RunRecurrenceCheck's shape -- errors are
+// logged, not fatal, so one bad tick doesn't kill the loop.
+func RunBucketCycleCheck(ctx context.Context, s *store.Store, interval time.Duration) {
+	ticker := time.NewTicker(interval)
+	defer ticker.Stop()
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-ticker.C:
+			n, err := s.RunBucketCycles(config.Now())
+			if err != nil {
+				log.Printf("ERROR [BucketCycleCheck]: %v", err)
+				continue
+			}
+			if n > 0 {
+				log.Printf("BucketCycleCheck: activated %d item(s)", n)
+			}
+		}
+	}
+}