docs: align RACI overview with actual Kosli roles (#291)

Brings the RACI matrix overview page in sync with the four roles
actually defined in [Roles in
Kosli](/administration/managing_users/roles_in_kosli).

**Changes in
`implementation_guide/phase_1/roles_and_responsibilities/overview.md`:**
- Added the missing **Snapshotter** role to the "Connecting
Responsibilities to Permissions" section (previously listed only
Admin/Member/Reader).
- Fixed the trailing "Roles in Kosli" reference — now a real link to
`/administration/managing_users/roles_in_kosli`, plus a link to
`/administration/managing_users/mapping_users_to_roles`.

**Drive-by fixes:**
- `app_developers.md` and `platform_engineers.md` had empty `[Kosli user
roles and permissions]()` links — now point to
`/administration/managing_users/roles_in_kosli` (matching the
already-correct links on `sponsors.md` and `security_compliance.md`).

The RACI table itself (Platform Engineer / Application Developer /
Security & Compliance / Sponsor) was left as-is — those are
*organizational* roles for implementation responsibilities, distinct
from Kosli platform roles, and they line up with the per-role pages and
`mapping_users_to_roles`.

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---
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Requested by: marko@kosli.com via Slack
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Co-authored-by: mintlify[bot] <109931778+mintlify[bot]@users.noreply.github.com>

Author: mintlify[bot]

implementation_guide/phase_1/roles_and_responsibilities/app_developers.md

@@ -73,7 +73,7 @@ To perform the responsibilities described above, users in this role typically ne
 
 Developers typically need to report attestations and manage flows for their applications. The Member role enables this. Some developers may only need visibility into deployments and compliance status, making the Reader role sufficient.
 
-Learn more about [Kosli user roles and permissions]().
+Learn more about [Kosli user roles and permissions](/administration/managing_users/roles_in_kosli).
 
 ## Where to start
 - [**Getting Started**](): Follow this if you're curious about how Kosli works behind the scenes

implementation_guide/phase_1/roles_and_responsibilities/overview.md

@@ -68,11 +68,12 @@ The RACI model helps teams and stakeholders know who to talk to, who drives a de
 
 ## Connecting Responsibilities to Permissions
 
-The RACI matrix above describes responsibilities during Kosli implementation. To perform these responsibilities, users need appropriate Kosli user roles (Admin, Member, or Reader) assigned in the platform.
+The RACI matrix above describes responsibilities during Kosli implementation. To perform these responsibilities, users need appropriate Kosli user roles (Admin, Member, Snapshotter, or Reader) assigned in the platform.
 
 Kosli user roles control what actions someone can perform in the Kosli system:
 - **Admin**: Full control, including user management and organization settings
 - **Member**: Can create and modify resources, manage service accounts, and configure integrations
+- **Snapshotter**: Can report environment snapshots and manage service accounts, with read-only access to other resources
 - **Reader**: Read-only access to view data and compliance status
 
-For guidance on which Kosli user role to assign based on organizational responsibilities, see Roles in Kosli.
+For guidance on which Kosli user role to assign based on organizational responsibilities, see [Roles in Kosli](/administration/managing_users/roles_in_kosli) and [Mapping users to roles](/administration/managing_users/mapping_users_to_roles).

implementation_guide/phase_1/roles_and_responsibilities/platform_engineers.md

@@ -80,7 +80,7 @@ To perform the responsibilities described above, users in this role typically ne
 
 Platform engineers need to set up flows, manage service accounts, configure integrations, and implement Kosli across teams. The Member role provides these capabilities. Lead platform engineers who manage the overall organizational setup may require Admin access to manage users and organization settings.
 
-Learn more about [Kosli user roles and permissions]().
+Learn more about [Kosli user roles and permissions](/administration/managing_users/roles_in_kosli).
 
 ## Where to start