feat(cards): add 'note' card type for readable markdown content

New card type renders body as styled markdown with no copy/fill/run
affordance. Glyph: ¶, color: --note.

Migration uses transaction to safely rebuild table constraint.
Checks both 'note' presence and modified_at column to catch
partial migration state.

internal/db/db.go

@@ -3,8 +3,10 @@ package db
 import (
 	"database/sql"
 	"errors"
+	"fmt"
 	"os"
 	"path/filepath"
+	"strings"
 
 	_ "modernc.org/sqlite"
 )
@@ -63,7 +65,7 @@ func (s *Store) migrate() error {
 			pinned      INTEGER NOT NULL DEFAULT 0,
 			deleted_at  TEXT,
 			card_type   TEXT
-				CHECK (card_type IN ('snippet', 'template', 'checklist', 'decision', 'link')
+				CHECK (card_type IN ('snippet', 'template', 'checklist', 'decision', 'link', 'note')
 				       OR card_type IS NULL),
 			card_data   TEXT,
 			use_count   INTEGER NOT NULL DEFAULT 0,
@@ -91,6 +93,58 @@ func (s *Store) migrate() error {
 	s.db.Exec(`ALTER TABLE entities ADD COLUMN title TEXT`)
 	s.db.Exec(`ALTER TABLE entities ADD COLUMN description TEXT`)
 
+	// Migrate CHECK constraint to include 'note' card type
+	var needsMigrate bool
+	row := s.db.QueryRow(`SELECT sql FROM sqlite_master WHERE type='table' AND name='entities'`)
+	var ddl string
+	if row.Scan(&ddl) == nil {
+		hasNote := strings.Contains(ddl, "'link', 'note'")
+		hasModified := strings.Contains(ddl, "modified_at")
+		needsMigrate = !hasNote || !hasModified
+	}
+	if needsMigrate {
+		tx, err := s.db.Begin()
+		if err != nil {
+			return err
+		}
+		defer tx.Rollback()
+
+		if _, err := tx.Exec(`ALTER TABLE entities RENAME TO _entities_migrate`); err != nil {
+			return fmt.Errorf("migrate rename: %w", err)
+		}
+		if _, err := tx.Exec(`CREATE TABLE entities (
+			id          TEXT PRIMARY KEY,
+			created_at  TEXT NOT NULL,
+			modified_at TEXT NOT NULL,
+			body        TEXT NOT NULL,
+			glyph       TEXT NOT NULL
+				CHECK (glyph IN ('todo', 'event', 'note')),
+			time_anchor TEXT,
+			completed_at TEXT,
+			pinned      INTEGER NOT NULL DEFAULT 0,
+			deleted_at  TEXT,
+			card_type   TEXT
+				CHECK (card_type IN ('snippet', 'template', 'checklist', 'decision', 'link', 'note')
+				       OR card_type IS NULL),
+			card_data   TEXT,
+			use_count   INTEGER NOT NULL DEFAULT 0,
+			last_used_at TEXT,
+			title       TEXT,
+			description TEXT
+		)`); err != nil {
+			return fmt.Errorf("migrate create: %w", err)
+		}
+		if _, err := tx.Exec(`INSERT INTO entities SELECT * FROM _entities_migrate`); err != nil {
+			return fmt.Errorf("migrate copy: %w", err)
+		}
+		if _, err := tx.Exec(`DROP TABLE _entities_migrate`); err != nil {
+			return fmt.Errorf("migrate drop: %w", err)
+		}
+		if err := tx.Commit(); err != nil {
+			return fmt.Errorf("migrate commit: %w", err)
+		}
+	}
+
 	return nil
 }
 

internal/db/entities.go

@@ -27,6 +27,7 @@ const (
 	CardChecklist CardType = "checklist"
 	CardDecision  CardType = "decision"
 	CardLink      CardType = "link"
+	CardNote      CardType = "note"
 )
 
 func ValidGlyph(s string) bool {
@@ -39,7 +40,7 @@ func ValidGlyph(s string) bool {
 
 func ValidCardType(s string) bool {
 	switch CardType(s) {
-	case CardSnippet, CardTemplate, CardChecklist, CardDecision, CardLink:
+	case CardSnippet, CardTemplate, CardChecklist, CardDecision, CardLink, CardNote:
 		return true
 	}
 	return false

internal/display/glyph.go

@@ -15,6 +15,7 @@ var cardGlyphMap = map[db.CardType]string{
 	db.CardChecklist: "☐",
 	db.CardDecision:  "⚖",
 	db.CardLink:      "↗",
+	db.CardNote:      "¶",
 }
 
 func DisplayGlyph(glyph db.Glyph, cardType *db.CardType) string {

internal/parse/grammar.go

@@ -27,6 +27,8 @@ var validCardTypes = map[string]string{
 	"checklist": "checklist",
 	"decision":  "decision",
 	"link":      "link",
+	"note":      "note",
+	"n":         "note",
 }
 
 func Parse(input string) (*Result, error) {

web/app.js

@@ -4,14 +4,14 @@
   const GLYPHS = {
     note: '—', todo: '○', event: '◇', reminder: '△',
     snippet: '◆', template: '◈', checklist: '☐',
-    decision: '⚖', link: '↗',
+    decision: '⚖', link: '↗', note: '¶',
   };
 
   const GLYPH_CLASSES = {
     note: 'glyph-note', todo: 'glyph-todo', event: 'glyph-event', reminder: 'glyph-reminder',
     snippet: 'glyph-snippet', template: 'glyph-template',
     checklist: 'glyph-checklist', decision: 'glyph-decision',
-    link: 'glyph-link',
+    link: 'glyph-link', note: 'glyph-note',
   };
 
   const PAGE_SIZE = 50;
@@ -121,7 +121,7 @@
 
   // ========== Grammar parser (mirrors Go parser) ==========
 
-  const VALID_CARDS = { card: 'snippet', c: 'snippet', snippet: 'snippet', template: 'template', checklist: 'checklist', decision: 'decision', link: 'link' };
+  const VALID_CARDS = { card: 'snippet', c: 'snippet', snippet: 'snippet', template: 'template', checklist: 'checklist', decision: 'decision', link: 'link', note: 'note', n: 'note' };
 
   function validateTime(s) {
     const parts = s.split(':');

web/index.html

@@ -64,6 +64,11 @@
                     <span class="type-name">decision</span>
                     <span class="type-hint">record a choice + rationale</span>
                 </button>
+                <button data-type="note" class="type-btn">
+                    <span class="type-glyph glyph-note">¶</span>
+                    <span class="type-name">note</span>
+                    <span class="type-hint">readable markdown content</span>
+                </button>
                 <button data-type="link" class="type-btn">
                     <span class="type-glyph glyph-link">↗</span>
                     <span class="type-name">link</span>

web/style.css

@@ -462,6 +462,7 @@ main.focus-peek .resize-handle { visibility: hidden; }
 .glyph-checklist { color: var(--remind); }
 .glyph-decision { color: var(--note); }
 .glyph-link { color: var(--event); }
+.glyph-note { color: var(--note); }
 
 .entity-content {
     flex: 1;