Mobile Phase 3a: read + write-supported Fundraising Grid surface

Adds the mobile-first Fundraising Grid (<768px): a lean MobileFundraisingGrid
that reads /api/fundraising/state once and renders an investor card list over
the active view (name, committed $, pipeline-stage chip, staleness-colored
recency, Existing-Investor accent, Priority corner; graveyard muted) with a
bottom-sheet view picker and search. Tap a card -> full-screen detail with
read-only commitments/contacts/notes plus edit sheets: log a note, pipeline
stage, set a reminder, and a "+ New" investor create flow with client-side
dedup typeahead.

All writes go through the targeted one-row endpoints (log-communication,
pipeline link, opportunities stage PATCH, reminders) — NEVER the whole-grid
PUT, which would race the multi-user grid (BRIEF §3a). FundraisingGridPage is
now a useIsMobile() wrapper over the renamed-but-untouched desktop grid and
the new mobile one (rules-of-hooks-safe; desktop unchanged).

Backend: inject a read-only opportunity_id into grid rows
(opportunity_id_by_source_row; added to both strip points) so the mobile detail
can PATCH a linked opp's stage directly. Earliest-opp-wins ordering keeps it
consistent with pipeline_stage and the link's canonical pick.

Editing an existing investor's name + contact pills stays read-only here
(deferred to P3b — needs a narrow per-row PATCH + pill editor).

Tests: test_grid_pipeline_link extended (opportunity_id inject/strip/round-trip);
36/36 backend green, render-smoke green.

backend/server.py

@@ -1596,8 +1596,8 @@ def sanitize_fundraising_grid(grid):
     # linked opportunity and injected on read — never persisted as row data (the GET handler
     # re-injects them after sanitize). The column DEFINITIONS persist like any other column
     # so their position / width / hidden state is kept.
-    _computed_row_values = ('longshot_followup', 'pipeline', 'pipeline_stage', 'reminder_status',
-                            'existing_investor', 'last_activity_at', 'staleness')
+    _computed_row_values = ('longshot_followup', 'pipeline', 'pipeline_stage', 'opportunity_id',
+                            'reminder_status', 'existing_investor', 'last_activity_at', 'staleness')
 
     clean_columns = []
     seen = set()
@@ -1698,12 +1698,17 @@ def pipeline_stage_by_source_row(conn):
     of truth, so this is always derived fresh and injected as read-only grid columns —
     never stored in the grid blob, where it could go stale."""
     out = {}
+    # ORDER BY created_at DESC so the EARLIEST opp is processed last and wins the overwrite —
+    # matching handle_pipeline_link's canonical choice (ORDER BY created_at LIMIT 1). The link
+    # enforces one live opp per investor, so multi-opp is an out-of-band anomaly; this just keeps
+    # the injection deterministic and consistent with opportunity_id_by_source_row if it occurs.
     for r in conn.execute(
         """
         SELECT fi.source_row_id AS srid, o.stage AS stage
         FROM opportunities o
         JOIN fundraising_investors fi ON o.fundraising_investor_id = fi.id
         WHERE o.deleted_at IS NULL
+        ORDER BY o.created_at DESC
         """
     ).fetchall():
         srid = str(r['srid'] or '')
@@ -1712,6 +1717,29 @@ def pipeline_stage_by_source_row(conn):
     return out
 
 
+def opportunity_id_by_source_row(conn):
+    """Return {grid source_row_id: live opportunity id} for every investor with a non-deleted
+    linked opportunity. Injected read-only alongside pipeline_stage so the mobile grid detail can
+    PATCH /api/opportunities/{id}/stage directly (the same endpoint the Pipeline board uses) — the
+    grid row otherwise carries no opp id. Never persisted; stripped on write like pipeline_stage."""
+    out = {}
+    # See pipeline_stage_by_source_row: earliest opp wins (ORDER BY created_at DESC + overwrite) so
+    # opportunity_id and pipeline_stage always reference the SAME opp, matching the link's canonical pick.
+    for r in conn.execute(
+        """
+        SELECT fi.source_row_id AS srid, o.id AS opp_id
+        FROM opportunities o
+        JOIN fundraising_investors fi ON o.fundraising_investor_id = fi.id
+        WHERE o.deleted_at IS NULL
+        ORDER BY o.created_at DESC
+        """
+    ).fetchall():
+        srid = str(r['srid'] or '')
+        if srid:
+            out[srid] = r['opp_id']
+    return out
+
+
 def last_activity_by_investor(conn):
     """Return {fundraising_investors.id: latest activity ISO timestamp} across captured
     emails (grid-linked) and logged communications — the per-investor recency signal behind
@@ -5562,6 +5590,7 @@ class CRMHandler(BaseHTTPRequestHandler):
         self._ensure_fundraising_state_row(conn)
         row = conn.execute("SELECT * FROM fundraising_state WHERE id = 'main'").fetchone()
         stage_by_row = pipeline_stage_by_source_row(conn)
+        opp_id_by_row = opportunity_id_by_source_row(conn)
         reminder_by_row = reminder_status_by_source_row(conn)
         existing_by_row = existing_investor_by_source_row(conn)
         recency_by_row = staleness_by_source_row(conn)
@@ -5592,6 +5621,9 @@ class CRMHandler(BaseHTTPRequestHandler):
             stage = stage_by_row.get(str(r.get('id') or ''))
             r['pipeline'] = bool(stage)
             r['pipeline_stage'] = stage or ''
+            # Live opportunity id for a linked row (read-only) — lets the mobile detail PATCH the
+            # stage on the opportunities endpoint; '' when the row isn't in the pipeline.
+            r['opportunity_id'] = opp_id_by_row.get(str(r.get('id') or ''), '')
             # Read-only reminder status, derived live from the reminders table (never stored
             # in the blob). '' = no open reminder; a saved view can filter on this column to
             # supersede the binary follow_up checkbox.