feature: Fully enable non-default ESP paths

[frhuelsz]

🔍 Description

Final PR in the series to allow for non-default ESP paths. This one gets rids of the last couple of usages of the ESP mount point path constants.

It also renames them and adds a doc comment about not using them in product code. The only remaing places where they are used:

• In HC parsing, when default behavior is desired. (only product code instance)
• In tests.
• In sample HC files.

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Enables non-default ESP mount paths by removing remaining hard-coded ESP path constants from product code paths and pivoting to using the runtime ESP mount path from context / Host Status.

Changes:

• Renames ESP path constants to DEFAULT_* variants and updates samples/tests/docs to use the renamed constants.
• Updates ESP path construction in subsystems/engine code to use ctx.esp_mount_path (and derived Host Status values) instead of compile-time constants.
• Updates offline-init logic to discover ESP mount path from Host Status rather than assuming /boot/efi.

Reviewed changes

Copilot reviewed 20 out of 20 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
report/esp-constant-usages.md	Updates the tracking report to reflect remaining/default-only constant usages.
crates/trident_api/src/samples/sample_hc.rs	Updates sample HC mounts to use DEFAULT_ESP_MOUNT_POINT_PATH.
crates/trident_api/src/constants.rs	Renames ESP constants to DEFAULT_* and adds “do not use” doc warnings.
crates/trident_api/src/config/host/storage/storage_graph/validation_tests.rs	Updates storage graph validation tests to the renamed ESP constant.
crates/trident_api/src/config/host/storage/mod.rs	Updates host storage tests to the renamed ESP constant.
crates/trident_api/src/config/host/storage/filesystem.rs	Updates default ESP mount detection/serde tests to the renamed constant.
crates/trident/src/subsystems/storage/osimage.rs	Updates ESP mount points in osimage tests to the renamed constant.
crates/trident/src/subsystems/storage/fstab.rs	Updates fstab tests to the renamed ESP constant.
crates/trident/src/subsystems/esp.rs	Switches ESP-relative path building to ctx.esp_mount_path and threads it through helpers.
crates/trident/src/init/offline/mod.rs	Discovers ESP mount path from Host Status rather than assuming default path.
crates/trident/src/engine/storage/encryption.rs	Updates encryption tests/functional tests to the renamed ESP constant.
crates/trident/src/engine/newroot.rs	Updates functional tests to use DEFAULT_ESP_RELATIVE_MOUNT_POINT_PATH.
crates/trident/src/engine/manual_rollback/mod.rs	Uses engine_context.esp_mount_path in rollback path construction.
crates/trident/src/engine/install_index.rs	Updates install index tests to the renamed ESP constant.
crates/trident/src/engine/context/mod.rs	Updates EngineContext::default() test/ft default ESP mount path.
crates/trident/src/engine/bootentries.rs	Updates bootentries tests/functional tests to the renamed ESP constant.
crates/trident/src/engine/boot/uki.rs	Removes dependency on the old constant and threads ESP mount path into UKI helpers.
crates/trident/src/engine/boot/grub.rs	Updates functional test to the renamed ESP constant.
crates/osutils/src/tabfile.rs	Updates osutils tabfile tests to the renamed ESP constant.
crates/docbuilder/src/main.rs	Updates docbuilder constant map to the renamed ESP constant.

[frhuelsz]

/AzurePipelines run [GITHUB]-trident-pr-e2e

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