refactor(config)!: reorganize processing settings

Move processing-related configuration keys out of [encoding] and [skip]
into a dedicated [processing] section.

Use [processing].skip_codecs, [processing].backup_dir,
[processing].only_if_smaller, [processing].verify_output, and
[processing].continue so the config structure matches the CLI help
sections.

Update README, man page, startup warnings, and debug output to use the
new configuration layout.

BREAKING CHANGE: config.toml keys for skip codecs and processing options
moved. Replace [skip].codecs with [processing].skip_codecs, and move
[encoding].backup_dir, [encoding].only_if_smaller,
[encoding].verify_output, and [encoding].continue to [processing].
Existing config files using the old keys must be updated.

1 files changed, 26 insertions, 52 deletions

diff --git a/README.md b/README.md
index 53678cf..fb13b92 100644
--- a/README.md
+++ b/README.md
@@ -155,10 +155,8 @@ ${XDG_CONFIG_HOME:-$HOME/.config}/transcode.sh/config.toml
 
 Use `--config-file FILE` to load an alternative path, or `--no-config` to skip
 configuration loading entirely. CLI flags generally take precedence over values
-in the config file. Skip codecs are additive by default: configured codecs and
-CLI codecs are merged unless `--skip-codec-override` is used. The file must be
-valid TOML — an unparseable file is a hard error. Requires `tomlq` when the
-file is present.
+in the config file. The file must be valid TOML — an unparseable file is a hard
+error. Requires `tomlq` when the file is present.
 
 **Example `config.toml`:**
 
@@ -166,11 +164,14 @@ file is present.
 [encoding]
 preset     = "av1"
 nice       = 10
-backup_dir = "backups"
 video_stream = "v:0"
 
-[skip]
-codecs = ["av1", "hevc"]
+[processing]
+skip_codecs = ["av1", "hevc"]
+backup_dir = "backups"
+only_if_smaller = false
+verify_output = true
+continue = false
 
 [size_report]
 enabled = true
@@ -181,44 +182,22 @@ verbose = false
 quiet   = false
 ```
 
-| Section | Key | Type | CLI equivalent |
-|---------|-----|------|----------------|
-| `[encoding]` | `preset` | string | `-p` |
-| `[encoding]` | `nice` | integer | `-N` |
-| `[encoding]` | `hwaccel` | string or boolean | `--hwaccel` / `--no-hwaccel` |
-| `[encoding]` | `video_stream` | string | `--video-stream` |
-| `[encoding]` | `backup_dir` | string | `--backup-dir` |
-| `[encoding]` | `verify_output` | boolean | `--verify-output` |
-| `[skip]` | `codecs` | array of strings | `-S` / `--skip-codec-override` |
-| `[size_report]` | `enabled` | boolean | `-s` / `--no-size-report` |
-| `[size_report]` | `file` | string | `--size-report-file` |
-| `[output]` | `ffmpeg_loglevel` | string | `--ffmpeg-loglevel` |
-| `[output]` | `quiet` | boolean | `-q` |
-| `[output]` | `verbose` | boolean | `-v` |
-
-> **Note:** `[skip] codecs` from the config file and `--skip-codec` from the
-> CLI are **merged** by default — both sources contribute to the skip list. Use
-> `--skip-codec-override` to ignore configured skip codecs and use only codecs
-> provided through `--skip-codec` for that run.
-
-> **Note:** `[encoding] hwaccel` accepts `false` (disable), `true` (use `auto`),
-> or a method string such as `"vaapi"` or `"cuda"`. CLI `--hwaccel`/`--no-hwaccel`
-> always takes precedence.
-
-> **Note:** `[encoding] backup_dir` must point to an existing directory. CLI
-> `--backup-dir` always takes precedence.
-
-> **Note:** `[encoding] video_stream` selects the input video stream that is
-> probed for preset helper variables. It defaults to `"v:0"`. Invalid config
-> values are ignored with a warning and the default is used. CLI
-> `--video-stream` always takes precedence. This setting does not change ffmpeg
-> stream mapping in presets.
-
-### Codec skip list (deprecated)
-
-The legacy `skip.conf` file is no longer read. If it still exists, a
-deprecation warning is printed at startup. Migrate its contents to
-`[skip] codecs` in `config.toml` and delete the old file.
+| Section | Key | Type | CLI equivalent | Note |
+|---------|-----|------|----------------|------|
+| `[encoding]` | `preset` | string | `-p` | |
+| `[encoding]` | `nice` | integer | `-N` | |
+| `[encoding]` | `hwaccel` | string or boolean | `--hwaccel` / `--no-hwaccel` | Accepts `false` (disable), `true` (use `auto`), or a method string such as `"vaapi"` or `"cuda"`|
+| `[encoding]` | `video_stream` | string | `--video-stream` | Selects the input video stream that is probed for preset helper variables. It defaults to `"v:0"`. Invalid config values are ignored with a warning and the default is used. This setting does not change ffmpeg stream mapping in presets. |
+| `[processing]` | `skip_codecs` | array of strings | `-S` / `--skip-codec-override` | Codecs defined here and codecs defined using `--skip-codec` from the CLI are **merged** by default. Use `--skip-codec-override` to ignore configured skip codecs and use only codecs provided through `--skip-codec` for that run. |
+| `[processing]` | `backup_dir` | string | `--backup-dir` | Must point to an existing directory. |
+| `[processing]` | `only_if_smaller` | boolean | `--only-if-smaller` / `--no-only-if-smaller` | |
+| `[processing]` | `verify_output` | boolean | `--verify-output` / `--no-verify-output` | |
+| `[processing]` | `continue` | boolean | `--continue` / `--no-continue` | |
+| `[size_report]` | `enabled` | boolean | `-s` / `--no-size-report` | |
+| `[size_report]` | `file` | string | `--size-report-file` | |
+| `[output]` | `ffmpeg_loglevel` | string | `--ffmpeg-loglevel` | |
+| `[output]` | `quiet` | boolean | `-q` | |
+| `[output]` | `verbose` | boolean | `-v` | |
 
 ## Usage
 
@@ -244,17 +223,12 @@ transcode.sh [OPTION] [--] FILE...
 | `--no-hwaccel` | Disable hardware acceleration (omit `-hwaccel` from ffmpeg invocation) |
 | `--video-stream STREAM_SELECTOR`, `--video-stream=STREAM_SELECTOR` | Select the input video stream to probe for preset helper variables, e.g. `v:0` or `v:1` (default: `v:0`) |
 
-### Skip options
-
-| Option | Description |
-|--------|-------------|
-| `-S LIST`, `--skip-codec LIST`, `--skip-codec=LIST` | Add codecs to the effective skip list (comma/space/colon separated) |
-| `--skip-codec-override` | Use only codecs from `--skip-codec`, ignoring `[skip].codecs` from config |
-
 ### Processing options
 
 | Option | Description |
 |--------|-------------|
+| `-S LIST`, `--skip-codec LIST`, `--skip-codec=LIST` | Add codecs to the effective skip list (comma/space/colon separated) |
+| `--skip-codec-override` | Use only codecs from `--skip-codec`, ignoring `[processing].skip_codecs` from config |
 | `-n`, `--dry-run` | Show what would be done; don't run ffmpeg |
 | `--backup-dir DIR`, `--backup-dir=DIR` | Copy originals to an existing backup directory before replacing them |
 | `-l`, `--only-if-smaller` | Only replace original if new file is smaller |