docs: add feature ideas catalog, time-decay scoring plan, and timeline issue doc

Ideas catalog (docs/ideas/): 25 feature concept documents covering future
lore capabilities including bottleneck detection, churn analysis, expert
scoring, collaboration patterns, milestone risk, knowledge silos, and more.
Each doc includes motivation, implementation sketch, data requirements, and
dependencies on existing infrastructure. README.md provides an overview and
SYSTEM-PROPOSAL.md presents the unified analytics vision.

Plans (plans/): Time-decay expert scoring design with four rounds of review
feedback exploring decay functions, scoring algebra, and integration points
with the existing who-expert pipeline.

Issue doc (docs/issues/001): Documents the timeline pipeline bug where
EntityRef was missing project context, causing ambiguous cross-project
references during the EXPAND stage.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/ideas/label-flow.md

@@ -0,0 +1,74 @@
+# Label Velocity
+
+- **Command:** `lore label-flow <from-label> <to-label>`
+- **Confidence:** 78%
+- **Tier:** 3
+- **Status:** proposed
+- **Effort:** medium — self-join on resource_label_events, percentile computation
+
+## What
+
+For a given label pair (e.g., "needs-review" to "approved"), compute median and P90
+transition times using `resource_label_events`. Shows how fast work moves through
+your process labels.
+
+Also supports: single label dwell time (how long does "in-progress" stay applied?).
+
+## Why
+
+Process bottlenecks become quantifiable. "Our code review takes a median of 3 days"
+is actionable data for retrospectives and process improvement.
+
+## Data Required
+
+All exists today:
+- `resource_label_events` (label_name, action, created_at, issue_id, merge_request_id)
+
+## Implementation Sketch
+
+```sql
+-- Label A → Label B transition time
+WITH add_a AS (
+    SELECT issue_id, merge_request_id, MIN(created_at) as added_at
+    FROM resource_label_events
+    WHERE label_name = ?1 AND action = 'add'
+    GROUP BY issue_id, merge_request_id
+),
+add_b AS (
+    SELECT issue_id, merge_request_id, MIN(created_at) as added_at
+    FROM resource_label_events
+    WHERE label_name = ?2 AND action = 'add'
+    GROUP BY issue_id, merge_request_id
+)
+SELECT
+    (b.added_at - a.added_at) / 3600000.0 as hours_transition
+FROM add_a a
+JOIN add_b b ON a.issue_id = b.issue_id OR a.merge_request_id = b.merge_request_id
+WHERE b.added_at > a.added_at;
+```
+
+Then compute percentiles in Rust (median, P75, P90).
+
+## Human Output
+
+```
+Label Flow: "needs-review" → "approved"
+
+  Transitions:  42 issues/MRs in last 90 days
+  Median:       18.5 hours
+  P75:          36.2 hours
+  P90:          72.8 hours
+  Slowest:      !234 Refactor auth (168 hours)
+```
+
+## Downsides
+
+- Only works if teams use label-based workflows consistently
+- Labels may be applied out of order or skipped
+- Self-join performance could be slow with many events
+
+## Extensions
+
+- `lore label-flow --dwell "in-progress"` — how long does a label stay?
+- `lore label-flow --all` — auto-discover common transitions from event data
+- Visualization: label state machine with median transition times on edges