docs: document file_type prefix convention and streamd daily command

README.md

@@ -49,11 +49,20 @@ Markdown files are named with a timestamp: `YYYYMMDD-HHMMSS [markers].md`
 
 For example: `20260131-210000 Task Streamd.md`
 
+An optional `_file_type` segment can follow the timestamp to classify the file:
+
+```
+YYYYMMDD-HHMMSS_<file_type> [markers].md
+```
+
+For example: `20260413-083000_daily.md` — the `daily` prefix is stored as the `file_type` dimension and propagates to all child shards.
+
 Within files, `@`-prefixed markers at the beginning of paragraphs or headings define how a shard is categorized.
 
 ## Commands
 
 - `streamd` / `streamd new` — Create a new timestamped markdown entry, opening your editor
+- `streamd daily [YYYYMMDD]` — Open today's daily file (or create it if missing); pass a date to open that day's file instead
 - `streamd todo` — Show all open tasks (shards with `@Task` markers), numbered for easy reference
 - `streamd todo N edit` — Edit task N in your editor, jumping to the task's line
 - `streamd todo N done` — Mark task N as done by inserting `@Done` after `@Task`

REQUIREMENTS.md

@@ -275,13 +275,18 @@ This allows conditional placements to override base placements.
 
 ### R15: File Name Format
 
-Files follow the pattern: `YYYYMMDD-HHMMSS [markers].md`
+Files follow the pattern: `YYYYMMDD-HHMMSS[_file_type] [markers].md`
 
 - `YYYYMMDD`: Date (8 digits, required)
 - `HHMMSS`: Time (4-6 digits, optional, pads with zeros)
+- `_file_type`: Optional alphanumeric prefix identifying the file type (e.g. `_daily`)
 - `[markers]`: Space-separated marker names extracted from file content
 
-**Extraction regex:** `^(?P<date>\d{8})(?:-(?P<time>\d{4,6}))?.+\.md$`
+**Extraction regex for datetime:** `^(?P<date>\d{8})(?:-(?P<time>\d{4,6}))?.+\.md$`
+
+**Extraction regex for file type:** `^\d{8}(?:-\d{4,6})?_([a-zA-Z0-9]+)`
+
+When a `_file_type` prefix is present it is stored in the `file_type` dimension of the root shard and propagates to all child shards.
 
 ### R16: Temporal Markers
 
@@ -387,6 +392,7 @@ Provide recursive search through the shard tree:
 | Command | Description |
 |---------|-------------|
 | `streamd new` | Create new timestamped file, open editor, rename with markers on close |
+| `streamd daily [YYYYMMDD]` | Open the earliest daily file for the given date (default: today in configured timezone), or create a new `_daily` file if none exists |
 | `streamd todo` | List all shards with `task: "open"`, numbered, hiding future tasks |
 | `streamd todo --show-future` | Include tasks with future dates in the todo listing |
 | `streamd todo N edit` | Edit task N in editor, cursor positioned at task line |
@@ -395,6 +401,23 @@ Provide recursive search through the shard tree:
 | `streamd timesheet` | Generate formatted timesheet report with expected/actual hours |
 | `streamd completions <shell>` | Generate shell completions (bash, zsh, fish, elvish, powershell) |
 
+### R21a: Daily Command Behavior
+
+`streamd daily [YYYYMMDD]` provides quick access to the daily journal entry for a given date.
+
+**Date resolution:**
+- If a `YYYYMMDD` argument is provided, it is parsed as the target date.
+- If no argument is given, today's date is used, interpreted in the repository timezone (from `.streamd.toml`, defaulting to UTC).
+
+**File lookup:**
+- All markdown files in the base folder are localized.
+- Files with `file_type = "daily"` whose root shard `moment` falls within the target date (in the configured timezone) are collected.
+- The file with the earliest `moment` is opened in `$EDITOR` (defaults to `vi`).
+
+**File creation:**
+- If no matching file is found, a new file is created at `<now_local>_daily.md` (e.g. `20260413-083000_daily.md`) containing `# ` and opened in the editor.
+- The `_daily` suffix is permanent — it identifies the file type and is not renamed after editing.
+
 ### R21: Todo Command Behavior
 
 **Task Numbering:**