feat(run): --features 与 --profile,以及那个不看 feature 的构建缓存条目

[Sunrisepeak]

feat(run): --features and --profile, and the cache entry that ignored them

The one scenario the design could not run

mcpp build and mcpp test have always taken --features and --profile.
mcpp run did not, so it could only execute whatever a previous build
happened to leave behind: there was no spelling of mcpp run that ran a release
artefact, or one built with a feature on.

That is the axis the whole device surface is built around. A board-support
package expresses its two environments — an emulator, a debug probe — AS
features, so

mcpp run --features hardware

is the command a developer types when the board arrives on their desk. It did
not exist, which made the design's own scenario a manifest edit rather than a
command.

--release and --dev come along as the shorthands the other verbs accept, and
--list-runners takes the same axes: which runners a project HAS depends on the
features, so reporting them without it answers a question nobody asked.

⚠️⚠️ And the pre-existing defect it uncovered

The build cache entry is keyed on (target, profile, cache mode). The OUTPUT
DIRECTORY is keyed on a fingerprint that includes the features. So an entry
written by mcpp build --features loud pointed at the loud directory, and the
next plain mcpp build matched it and reported success in 0.00s — serving a
featured artefact to a request that had none.

Measured: three consecutive builds of one project printed quiet, LOUD,
LOUD. The third had no feature on.

The entry now records its feature set, normalised so a,b and b a are one
request, and both fast paths compare it. Absent on older caches, which reads as
"no features" — correct for a request that has none, a miss otherwise, which is
the safe direction.

⭐ The run fast path additionally declines whenever either new axis is set, for
the reason --cache and --profile already bypass cmd_build's: the cached
graph was generated without them, and accepting a flag to ignore it is worse
than refusing it.

tests/e2e/337 covers both halves and fails without this change.

97/97 unit; e2e 87, 88, 130-131, 327, 332-337 green.