Show real mapping grammar in --help, make --via repeatable, trim comments

- -l/-r/-d now show their actual grammar as the clap value name
  (<[BIND:]PORT:HOST:PORT>, <[BIND:]PORT>) instead of a generic <SPEC>,
  matching vmic's convention of showing real syntax in --help. The
  grammar is no longer also repeated in the flag's help text, since the
  value name already carries it.
- --via changes from a single comma-separated flag to a repeatable one
  (Vec<String> + value_delimiter = ','), so both `--via a --via b` and
  `--via a,b` work and can be mixed. commands/mod.rs's edits_from_mapping
  no longer needs to split the string itself - clap does it.
- Trimmed CLI help text that restated grammar/rationale already covered
  by the value name or by --via being required.
- Normalized code comments for tone/format consistency: dropped
  cross-references to vmic's own internals as justification (this
  codebase should read as self-contained), removed markdown-style
  *emphasis* asterisks that don't render in plain comments, tightened
  several run-on sentences into plain declarative ones, and fixed one
  comment in wipe.rs that inaccurately described close_instance's force
  path (it sends SIGKILL, not SIGTERM).
- spec/porthole-spec.md's --via row updated to document the repeatable
  form alongside comma-separated.

Cargo.toml/Cargo.lock/atomic.rs also carry an external toml crate bump
and formatting pass picked up from the working tree.

Cargo.lock

@@ -306,11 +306,11 @@ dependencies = [
 
 [[package]]
 name = "serde_spanned"
-version = "0.6.9"
+version = "1.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bf41e0cfaf7226dca15e8197172c295a782857fcb97fad1808a166870dee75a3"
+checksum = "6662b5879511e06e8999a8a235d848113e942c9124f211511b16466ee2995f26"
 dependencies = [
- "serde",
+ "serde_core",
 ]
 
 [[package]]
@@ -352,44 +352,42 @@ dependencies = [
 
 [[package]]
 name = "toml"
-version = "0.8.23"
+version = "1.1.4+spec-1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dc1beb996b9d83529a9e75c17a1686767d148d70663143c7854d8b4a09ced362"
-dependencies = [
- "serde",
- "serde_spanned",
- "toml_datetime",
- "toml_edit",
-]
-
-[[package]]
-name = "toml_datetime"
-version = "0.6.11"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "22cddaf88f4fbc13c51aebbf5f8eceb5c7c5a9da2ac40a13519eb5b0a0e8f11c"
-dependencies = [
- "serde",
-]
-
-[[package]]
-name = "toml_edit"
-version = "0.22.27"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "41fe8c660ae4257887cf66394862d21dbca4a6ddd26f04a3560410406a2f819a"
+checksum = "3aace63f4bbcdfc2c965b059de67119c89c4017a70d633be6c104910f67056f5"
 dependencies = [
  "indexmap",
- "serde",
+ "serde_core",
  "serde_spanned",
  "toml_datetime",
- "toml_write",
+ "toml_parser",
+ "toml_writer",
  "winnow",
 ]
 
 [[package]]
-name = "toml_write"
-version = "0.1.2"
+name = "toml_datetime"
+version = "1.1.1+spec-1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5d99f8c9a7727884afe522e9bd5edbfc91a3312b36a77b5fb8926e4c31a41801"
+checksum = "3165f65f62e28e0115a00b2ebdd37eb6f3b641855f9d636d3cd4103767159ad7"
+dependencies = [
+ "serde_core",
+]
+
+[[package]]
+name = "toml_parser"
+version = "1.1.3+spec-1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d38ac1cf9b95face32296c0a3ede1fdc270627c9d9c02a7274dd6d960dc4d56"
+dependencies = [
+ "winnow",
+]
+
+[[package]]
+name = "toml_writer"
+version = "1.1.2+spec-1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7d56353a2a665ad0f41a421187180aab746c8c325620617ad883a99a1cbe66d2"
 
 [[package]]
 name = "unicode-ident"
@@ -426,12 +424,9 @@ dependencies = [
 
 [[package]]
 name = "winnow"
-version = "0.7.15"
+version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "df79d97927682d2fd8adb29682d1140b343be4ac0f08fd68b7765d9c059d3945"
-dependencies = [
- "memchr",
-]
+checksum = "23b97319f7b8343df12cc98938e5c3eb436064524c8d2b4e30a1d3a36eecdf81"
 
 [[package]]
 name = "zmij"