Dashboard + palette + analyze screen; consolidated categorization rules.

UI restructuring:

- Dashboard (`screen_dashboard.cpp`, `screen_idx = 6`) is the new home
  screen at boot. Reads Overview / Health / Analysis / Modules from
  the current System every frame; per-module rows list parts grouped
  by `connector_type` and a Power/Gnd inference summary (yellow when
  any name-Power signal is refuted). Scrollable via PgUp/PgDn/Home/End.
  Letter shortcuts: `c`=console, `s`=search, `p`=plug (alias of
  connect), `t`=set-type, `e`=explore, `n`=net, `a`=analyze, `q`=quit.
- Global Ctrl-P palette (`screen_palette.cpp`) — fuzzy-finds over
  registered commands + module / signal names. Activation runs the
  bare command or jumps to the matching screen with state seeded.
- Unified analyze screen (`screen_analyze.cpp`, `screen_idx = 7`):
  tabbed layout (`Issues / Groups / Types`), Tab or ←→ to switch
  tabs, ↑/↓ to navigate the focused list. Replaces the previous
  shell-bouncing `[v]erify` shortcut — `verify` content is now in
  the Issues tab. Types tab attaches the decision rationale to each
  signal row (fan-out / voltage / hard floor).
- Context help panel: `RenderHelpPanel(title, entries)` in
  `tui_helpers.{hpp,cpp}` rendered on the right of every screen.
- Console (former "log") rename: screen 0 is `[c]onsole` in the UI
  and "console" in its help-panel title. The underlying screen and
  the shell prompt are unchanged.
- Esc from any non-home screen returns to the dashboard. The
  dashboard itself swallows Esc; quit via `q` / the `quit` command.
  `quit` now calls `screen_ptr->Exit()` directly so it works from
  any screen including via the palette.

Signal type inference:

- `Signal::type` defaults to `Other` — auto-inference no longer
  happens at construction.
- `infer_signal_types(System*)` is called at the end of every load.
  Three rules: GndShield from name alone; Power requires name match
  + a hard fan-out floor (< 3 pins = always Other, regardless of
  name or voltage) + at least one positive structural signal
  (fan-out ≥ 4 OR voltage pattern in the name like `3V3`, `5V`).
- Thresholds exposed in `analysis.hpp` (`POWER_FANOUT_HARD_FLOOR`,
  `POWER_FANOUT_CONFIRM_MIN`, `has_voltage_pattern`) so the analyze
  screen can render the same rationale without duplicating logic.
- `set-signal-type` still wins; save/restore round-trips the type.

Analysis groups & anomalies:

- New `GroupKind::DiffBus` — ≥ 2 diff pairs sharing the same
  outer-stem with consecutive integer indices are aggregated into a
  single bus (`MDI[0..3]_P/N`). `MDI0` and `PCIE_TX_0` index forms
  both accepted. Solo pairs under a bus-able stem fall back to
  `DiffPair`.
- New `AnomalyKind::DiffBusGap` for missing lanes.

Documentation:

- `DESIGN.md`: dedicated "Categorization rules (normative)" section
  consolidating signal type, NC origin, signal groups, anomalies,
  component kind, and connector wiring rules with exact thresholds
  and decision order.
- `doc/user/analysis.md` (new): user-facing version of the same
  rules in plain language. Linked from `doc/user/index.md`.

Tests: +6 new cases (62 total). Adjusted `test_persist.cpp` to set
the signal type explicitly in the fixture (no more auto-inference).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/tui/tui.hpp

@@ -110,6 +110,28 @@ class Tui {
     int net_sig_idx;
     int net_focus_idx;
 
+    // ---- Dashboard scroll state (0 = top; grows as the user scrolls down) ----
+    int dashboard_scroll_offset = 0;
+
+    // ---- Analyze screen state (unified verify + analyze) ----
+    int analyze_focus_idx = 0;       ///< 0=issues 1=groups 2=types
+    std::vector<std::string> analyze_issues;
+    std::vector<std::string> analyze_groups;
+    std::vector<std::string> analyze_types;
+    int analyze_issue_idx = 0;
+    int analyze_group_idx = 0;
+    int analyze_type_idx = 0;
+
+    // ---- Command palette (global, fuzzy-find over commands + objects) ----
+    bool palette_open = false;
+    std::string palette_query;
+    int palette_idx = 0;
+    // Rebuilt every frame from <query, sys>: label shown to the user.
+    std::vector<std::string> palette_labels;
+    // Parallel kind/payload for each label. kind: 'c'=command, 'm'=module,
+    // 's'=signal. payload: command name / module name / "module\tsignal".
+    std::vector<std::pair<char, std::string>> palette_items;
+
     // ---- Signal-type popup (shared between net + explore screens) ----
     bool sigtype_dialog_open = false;
     std::string sigtype_dialog_mod;
@@ -180,7 +202,14 @@ private:
     ftxui::Component BuildSettypeScreen();
     ftxui::Component BuildExploreScreen();
     ftxui::Component BuildNetScreen();
+    ftxui::Component BuildDashboardScreen();
+    ftxui::Component BuildAnalyzeScreen();
     ftxui::Component BuildSignalTypeModal();
+    ftxui::Component BuildPaletteModal();
+    // Open palette (resets query/index, builds initial list).
+    void OpenPalette();
+    // Execute the currently-highlighted palette entry.
+    void ActivatePaletteEntry();
 };
 
 #endif // _TUI_HPP_