internal: Add MarshalJSON to resource types that inherited one by promotion

[denik]

12 of the 33 resource types embed BaseResource plus a member that declares its own
MarshalJSON (an SDK type, or an inner *Config). Go promotes that method to the outer
type, so json.Marshal serializes only that member's fields and silently drops
everything else on the struct: id, url, lifecycle, modified_status and
permissions.

PostgresProject -> {"project_id":"proj"}

bundle/direct/dresources/serialize_test.go was written for exactly this failure mode,
but only pointed at StateType and RemoteType. Pointing it at InputConfigType too
reports all 12. Each gets the same two marshalers the other 21 types already have.

Bundle config is normally read and written through libs/dyn, which walks the struct
itself and never calls these marshalers, so this is a latent trap rather than live
corruption - no golden output moves. No changelog entry for that reason.

cluster_policies is skipped on the InputConfigType surface, with the reason in a
comment: its definition is typed any and deliberately shadows
compute.CreatePolicy.Definition (a string) so the policy document can be authored as
inline YAML, and marshal.Unmarshal hands the whole payload to the embedded member, so
the shadowed string comes back holding the raw JSON text and reads as a lost field. It
loses exactly those two fields today and nothing else.

Side effect worth naming

The new MarshalJSON uses a value receiver, per the convention across
bundle/config/resources/. For the 7 Postgres types that matters beyond style: the inner
*Config declares MarshalJSON on a pointer receiver, so on main only *T satisfied
json.Marshaler and value-marshalling silently fell back to plain encoding/json - a
second code path that ignores ForceSendFields. A value receiver collapses the two.

Counting that asymmetry (*T marshals itself, T does not) across all 34 adapters and 3
surfaces: 14 on main, 7 here. The 7 remaining are pre-existing and untouched - 6
Postgres*Config reachable as StateType via type alias, plus Secret. They are latent
too (the state path marshals pointers throughout), and the round-trip test cannot detect
them, since it builds values with reflect.New and so only ever marshals a pointer.
Left for a follow-up rather than fixed here, to keep this PR to one change.

[eng-dev-ecosystem-bot]

Integration test report

Commit: f87d55a

Run: 34103852138

	Env	💚​RECOVERED	✅​pass	🙈​skip	Time
💚​	aws linux	1	275	15	6:46
💚​	aws windows	1	277	13	3:55
💚​	azure linux	1	274	15	6:32
💚​	azure windows	1	276	13	4:09
💚​	gcp linux	1	275	15	7:33
💚​	gcp windows	1	277	13	4:10

	Test Name	aws linux	aws windows	azure linux	azure windows	gcp linux	gcp windows
💚​	TestAccept	💚​R	💚​R	💚​R	💚​R	💚​R	💚​R

Top 6 slowest tests (at least 2 minutes):

duration	env	testname
3:59	gcp windows	TestAccept
3:58	azure linux	TestAccept
3:56	aws linux	TestAccept
3:53	gcp linux	TestAccept
3:44	azure windows	TestAccept
3:34	aws windows	TestAccept