rill [APP-538] feat: canvas default filter support

This PR adds support for specifying default time, dimension and measure filters to apply when loading a Canvas dashboard for the first time. When using the builder surface in Rill Developer, the workspace provides a quick way to save the currently selected filters as default, which would propagate to the YAML as metrics SQL statements:

type: canvas
defaults:
  time_range: 6h as of latest/m+1m
  filters:
    AdBids_metrics: (publisher IN ('Facebook', 'Google')) AND (publisher IN (SELECT publisher
      FROM metrics_view HAVING total_records > 200))

To support the use of multiple metrics views across a single canvas, these metrics SQL filters are keyed with the name of the underlying metrics view.

Filters are handled on a per-metrics-view basis via instances of the new FilterState class
Filter consolidation and rendering across multiple FilterState classes happens through the new FilterManager
URL filters are keyed with a string that takes the form f.{{metrics_view_name}}
Each FilterState class has actions on it that allow for filter state manipulation
The FilterManager class has proxies for these functions to call them across multiple FilterState classes
Consolidation of the namespace across multiple metrics views currently assumes that all dimensions/measures with equivalent identifiers are the same
Canvas initialization now happens through the CanvasProvider component no matter where a Canvas is rendered
When adding a filter for a measure/dimension that exists across multiple metrics views, it is added to each FilterState class (and to the URL) independently, though the actual URL navigation is batched for each user action
Canvas loading, url param syncing and redirecting happens through the onUrlChange function as well as updated getters and setters in canvas/state-managers.ts
Removes use of RuntimeProvider for embeds, sets the runtime in the topmost layout load function instead
A new "save defaults" button is added to update the YAML defaults with the current filter state
Refactors canvas time state management to use TimeManager and TimeState classes

Outstanding items:

[x] Update designs (and implementation) to reflect "pin" behavior rather than lock @Di7design
[x] Remove old Filter class if possible
[x] Ensure changes did not break Explore
[x] Ensure prior filter strings (without scoped metrics view) work as intended
[x] Fix tests
[x] Abstract UI filter parsing method and apply to defaults
[x] Fix issue with measure filter pills not updating on first apply
[x] Update CanvasFilterButton to display labels rather than unique ids
[x] Match sidebar design to Figma
[x] Add pinning capability to measures
[x] Resolve issue where unpinning does not immediately reflect in pill
[x] Add "saved as default" state to button when viewing defaults
[x] Resolve issue where filter dropdown reopens after applying selections
[ ] Bring back measure-specific dimension lists

Checklist:

[x] Covered by tests
[x] Ran it and it works as intended
[x] Reviewed the diff before requesting a review
[x] Checked for unhandled edge cases
[x] Linked the issues it closes
[x] Checked if the docs need to be updated. If so, create a separate Linear DOCS issue
[ ] Intend to cherry-pick into the release branch
[x] I'm proud of this work!

[!NOTE] Adds per-metrics-view canvas filtering with pinning and saved defaults, updates URL/schema and parser, refactors initialization/embeds, and introduces new UI to manage and display default/pinned filters.

Canvas filtering overhaul:

Introduces per-metrics-view filtering via FilterManager and MetricsViewFilter with consolidated UI/state.

Adds default filters and pinning (save/clear defaults; pinned chips), new inspector tabs, and read-only chips.

Updates URL schema to scoped filters (f.{metrics_view}) and batching of navigation.

Protocol & API:

Extends CanvasSpec with pinned_filters; CanvasPreset with filter_expr; updates Swagger/TS/Go protobufs.

Parser reads filters.pinned and defaults.filters from YAML.

Runtime/initialization:

New handleCanvasStoreInitialization and onUrlChange; removes RuntimeProvider for embeds; sets runtime in layout.

UI components:

New SaveDefaultsButton, default filters display; enhanced Chip (pin/gray), filter buttons/chips; time/comparison tweaks.

Embeds/routes:

Canvas embed and app routes refactored to initialize/store canvas and sync URL.

Cleanup & tests:

Removes old Filters class; updates bookmark handling and tests to new comparison/filters.

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