feat(config): add file_picker_dir setting for document file picker (#704)

## Summary

- Add `documents.file_picker_dir` config option (TOML +
`MICASA_FILE_PICKER_DIR` env var) to control the starting directory of
the document file picker
- Default to the system Downloads folder (`~/Downloads`) via
`xdg.UserDirs.Download` for cross-platform support (Linux XDG, macOS,
Windows)
- Graceful fallback chain: configured dir → Downloads → cwd → `"."`

closes #700

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: cpcloud

cmd/micasa/main.go

@@ -142,8 +142,9 @@ func (cmd *runCmd) Run() error {
 	}
 
 	opts := app.Options{
-		DBPath:     dbPath,
-		ConfigPath: config.Path(),
+		DBPath:        dbPath,
+		ConfigPath:    config.Path(),
+		FilePickerDir: cfg.Documents.ResolvedFilePickerDir(),
 	}
 
 	chatCfg := cfg.LLM.ChatConfig()

internal/app/forms.go

@@ -2416,11 +2416,15 @@ func (m *Model) newDocumentFilePicker(title string) *huh.FilePicker {
 	if h < 5 {
 		h = 5
 	}
-	// Resolve to absolute path so filepath.Dir can compute the real parent;
-	// the default "." stays stuck (filepath.Dir(".") == ".").
-	dir, err := os.Getwd()
-	if err != nil {
-		dir = "."
+	// Use the configured starting directory (defaults to ~/Downloads).
+	// Fall back to cwd if the configured dir is empty.
+	dir := m.filePickerDir
+	if dir == "" {
+		var err error
+		dir, err = os.Getwd()
+		if err != nil {
+			dir = "."
+		}
 	}
 	short := "\x1b[22m" + dimPath.Render("in "+shortenHome(dir))
 	return huh.NewFilePicker().

internal/app/model.go

@@ -180,6 +180,7 @@ type Model struct {
 	llmClient             *llm.Client
 	llmConfig             *llmConfig // saved for extraction client creation
 	llmExtraContext       string     // user-provided context appended to prompts
+	filePickerDir         string     // starting directory for document file picker
 	ex                    extractState
 	pull                  pullState
 	chat                  *chatState // non-nil when chat overlay is open
@@ -259,6 +260,7 @@ func NewModel(store *data.Store, options Options) (*Model, error) {
 		llmClient:       client,
 		llmConfig:       options.LLMConfig,
 		llmExtraContext: extraContext,
+		filePickerDir:   options.FilePickerDir,
 		ex: extractState{
 			extractionProvider:  options.ExtractionConfig.Provider,
 			extractionBaseURL:   options.ExtractionConfig.BaseURL,

internal/app/types.go

@@ -226,6 +226,7 @@ type detailContext struct {
 type Options struct {
 	DBPath           string
 	ConfigPath       string
+	FilePickerDir    string     // starting directory for document file picker
 	LLMConfig        *llmConfig // nil if LLM is not configured
 	ExtractionConfig extractionConfig
 }

internal/config/config.go

@@ -212,6 +212,30 @@ type Documents struct {
 	// CacheTTLDays is deprecated; use CacheTTL instead. Kept for backward
 	// compatibility. Bare integer interpreted as days.
 	CacheTTLDays *int `toml:"cache_ttl_days,omitempty" env:"MICASA_CACHE_TTL_DAYS"`
+
+	// FilePickerDir is the starting directory for the document file picker.
+	// Default: the system Downloads folder (e.g. ~/Downloads).
+	FilePickerDir string `toml:"file_picker_dir" env:"MICASA_FILE_PICKER_DIR"`
+}
+
+// ResolvedFilePickerDir returns the starting directory for the file picker.
+// Uses the configured value if set and the directory exists, otherwise falls
+// back to the system Downloads folder, then the current working directory.
+func (d Documents) ResolvedFilePickerDir() string {
+	if d.FilePickerDir != "" {
+		if info, err := os.Stat(d.FilePickerDir); err == nil && info.IsDir() {
+			return d.FilePickerDir
+		}
+	}
+	if dir := xdg.UserDirs.Download; dir != "" {
+		if info, err := os.Stat(dir); err == nil && info.IsDir() {
+			return dir
+		}
+	}
+	if dir, err := os.Getwd(); err == nil {
+		return dir
+	}
+	return "."
 }
 
 // CacheTTLDuration returns the resolved cache TTL as a time.Duration.
@@ -1012,6 +1036,10 @@ model = "` + DefaultModel + `"
 # Default: 30d.
 # cache_ttl = "30d"
 
+# Starting directory for the document file picker.
+# Default: system Downloads folder (~/Downloads on most systems).
+# file_picker_dir = "/home/user/Documents"
+
 [extraction]
 # Timeout for pdftotext. Go duration syntax: "30s", "1m", etc. Default: "30s".
 # Increase if you routinely process very large PDFs.

internal/config/config_test.go

@@ -623,6 +623,7 @@ func TestEnvVars(t *testing.T) {
 		"MICASA_MAX_DOCUMENT_SIZE":      "documents.max_file_size",
 		"MICASA_CACHE_TTL":              "documents.cache_ttl",
 		"MICASA_CACHE_TTL_DAYS":         "documents.cache_ttl_days",
+		"MICASA_FILE_PICKER_DIR":        "documents.file_picker_dir",
 		"MICASA_EXTRACTION_MODEL":       "extraction.model",
 		"MICASA_MAX_EXTRACT_PAGES":      "extraction.max_extract_pages",
 		"MICASA_EXTRACTION_ENABLED":     "extraction.enabled",
@@ -1120,3 +1121,45 @@ extra_context = "Portland house."
 	assert.Equal(t, chat.Thinking, ex.Thinking)
 	assert.Equal(t, chat.ExtraContext, ex.ExtraContext)
 }
+
+// --- FilePickerDir ---
+
+func TestResolvedFilePickerDir_ConfiguredDirExists(t *testing.T) {
+	t.Parallel()
+	dir := t.TempDir()
+	d := Documents{FilePickerDir: dir}
+	assert.Equal(t, dir, d.ResolvedFilePickerDir())
+}
+
+func TestResolvedFilePickerDir_ConfiguredDirMissing(t *testing.T) {
+	t.Parallel()
+	d := Documents{FilePickerDir: "/nonexistent/path/that/does/not/exist"}
+	result := d.ResolvedFilePickerDir()
+	// Should fall back to Downloads or cwd, not the missing dir.
+	assert.NotEqual(t, "/nonexistent/path/that/does/not/exist", result)
+	assert.NotEmpty(t, result)
+}
+
+func TestResolvedFilePickerDir_EmptyFallsBackToDownloadsOrCwd(t *testing.T) {
+	t.Parallel()
+	d := Documents{}
+	result := d.ResolvedFilePickerDir()
+	assert.NotEmpty(t, result)
+}
+
+func TestFilePickerDir_FromTOML(t *testing.T) {
+	t.Parallel()
+	dir := t.TempDir()
+	path := writeConfig(t, "[documents]\nfile_picker_dir = '"+dir+"'\n")
+	cfg, err := LoadFromPath(path)
+	require.NoError(t, err)
+	assert.Equal(t, dir, cfg.Documents.FilePickerDir)
+}
+
+func TestFilePickerDir_FromEnv(t *testing.T) {
+	dir := t.TempDir()
+	t.Setenv("MICASA_FILE_PICKER_DIR", dir)
+	cfg, err := LoadFromPath(noConfig(t))
+	require.NoError(t, err)
+	assert.Equal(t, dir, cfg.Documents.FilePickerDir)
+}